Seminars

Past seminars at IRF in Kiruna



Autumn Semester 2004

21 Dec. Dr Mats Holmström (IRF-K)
9 Dec. Dr Yoshifumi Futaana (IRF-K), Energetic Neutral Atoms around Mars - Latest results from NPD on board Mars Express. [Abstract]
2 Dec. Dr Peter Dalin (IRF-K), Part I. Case study of the role of neutral air turbulence in the PMSE variations. Part II. Concept and technique for the processing of NLC digital photographs. [Abstract]
25 Nov. Andreas Ekenbäck (IRF-K), Using the Flash code for MHD simulations - description of a testcase. [Abstract]
12 Nov. Tomas Hode (Swedish Museum of Natural History), Astrobiology missions to Mars. [Abstract]
11 Nov. Prof. Sheila Kirkwood (IRF-K), Polar Mesosphere Winter Echoes - new results from statistics and from radar interferometry. [Abstract]
9 Nov. Docent Jan-Erik Wahlund (IRF-Uppsala), The latest news from Titan.
4 Nov. Prof. Anatol Guglielmi (Institute of Physics of the Earth, Moscow), Ponderomotive forces in space physics. [Abstract]
2 Nov. Prof. Syun-Ichi Akasofu (International Arctic Research Center, Alaska), Long-standing unsolved problems in solar physics and magnetospheric physics. [Abstract]
29 Oct. Prof. Martin Friedrich ( Tech. Univ. Graz), A recent model of the lower ionosphere based on sounding rocket and EISCAT observations and neural network analysis.
28 Oct. Grigory Nikulin (IRF-K), Internal-gravity and Rossby waves. [Abstract]
21 Oct. Dr Masatoshi Yamauchi (IRF-K), Concentration of Aurora Arc from viewpoint of Alfvén wave reflection at Ionosphere. [Abstract]
30 Sept. Dr Shu T. Lai (Air Force Research Laboratory, Space Weather Center of Excellence), High-Level Spacecraft Charging at Geosynchronous Altitudes: A Statistical Study. [Abstract]
9 Sept. Prof. Sandra C. Chapman (Univ. of Warwick, UK), PIC Simulations of Reforming Quasiperpendicular Collisionless Shocks - Consequences for Particle Acceleration. [Abstract]
9 Sept. Prof. Sandra C. Chapman (Univ. of Warwick, UK), Complexity, Models, Methods, and Examples from Plasma Physics and Astrophysics.

Abstracts

Prof. Sandra C. Chapman (Univ. of Warwick, UK), PIC simulations of reforming quasiperpendicular collisionless shocks - consequences for particle acceleration.


It has been suggested that supercritical shocks provide a variety of
mechanisms for particle acceleration leading to cosmic ray generation. PIC
simulations of quasiperpendicular shocks have recently shown that for
certain parameters the shock solution is no longer static- as found in
previous Hybrid simulations- but rather reforms on the gyroscales of the
ions. These parameters, in particular low upstream proton thermal speed as
compared to the inflow speed, are favoured at SNRs and at the heliospheric
termination shock. This talk will focus on the initial stages of particle
acceleration in reforming shocks from the background to a suprathermal
'injection' population which can then Fermi accelerate to cosmic ray
energies.

Dr Shu T. Lai (Air Force Research Laboratory, Space Weather Center of Excellence), High-Level Spacecraft Charging at Geosynchronous Altitudes: A Statistical Study.

The onset of spacecraft charging at geosynchronous altitudes occurs at a critical value of the space plasma electron temperature for a given spacecraft surface. We review the theoretical formulation and computational results and compare the results with the Los Alamos National Laboratory spacecraft charging observations. The observations show that the onset of charging occurs at a critical temperature in almost every charging event, no matter which satellite, which year, and which month. It is also observed that the critical temperature values remain the same no matter in eclipse or in sunlight.

Dr Masatoshi Yamauchi (IRF-K), Concentration of Aurora Arc from viewpoint of Alfvén wave reflection at Ionosphere.

[past observation]: While it is well known that the aurora activity is strongly controlled by the solar wind input, not all the controlling factors of actual aurora intensity, even the statistical one, is not well known. One obvious controlling factor is the ionospheric conductivity. High conductance (summer) favors large potential drop over the polar cap and total current intensity [e.g., Fujii et al., 1981; Fujii and Iijima, 1987; Yamauchi and Araki, 1989; Lu et al., 1994] and subsequent joule dissipation. However, peak density of the field-aligned current is higher during low conductance in winter [Newell and Meng, 1996].

[my model #1]: Using simple wave reflection model [Sato and Iijima, 1980; Kan and Sun, 1985], I have simulated the effect of local conductivity enhancement due to the field-aligned current (this represents the precipitation). Just including the conductivity enhancement into the linear wave reflection system, we can include the positive feedback of the enhancement of ionospheric conductivity and intensification of field-aligned current through the conductivity gradient. The simulation shows larger localization of the field-aligned current for low background conductivity because the ratio between the enhanced conductance and the background conductance is larger for low background conductance.

[my model #2]: In addition I made a simple calculation to examine the seasonal (ionospheric conductivity) effect on the ionospheric joule dissipation. Since the decay time of the magnetospheric energy is counter proportional to the total dissipation by the both hemispheres, this has clear semi-annual peak. Since input energy to a given point is proportional this decay time multiplied by the local conductivity, we can easily predict the famous semi-annual variation of nightside geomagnetic activities (in Kp and AL indices) and annual variation of dayside activity even if we ignore the semi-annual variation of energy input from the solar wind by the geometrical effect (Russell-McPerron effect).

Prof. Anatol Guglielmi (Institute of Physics of the Earth, Moscow), Ponderomotive forces in space physics.

This report consists of two parts. The first part in effect answers the question: Why is it in many cases preferable to use ponderomotive forces instead of the Lorentz force in space physics, especially when studying the acceleration of ions by electromagnetic waves? We shall consider the Abraham, Barlow, Lundin-Hultqvist, and Miller ponderomotive forces, as well as the so-called Bolotovsky-Serov ponderomotive drift. The second part is devoted to some interesting manifestations of the ponderomotive forces in space plasmas acceleration of the polar wind and deceleration of the solar wind, plasma cavity formation, anharmonicity of the standing Alfvén waves, resonant acceleration of heavy ions, etc. The most important conclusion is that ponderomotive acceleration of ions by Alfvén waves is a fundamental process in terrestrial magnetospheric- and celestial plasmas. Ponderomotive acceleration may transfer energy and momentum to plasmas, leading to plasma outflow at small- as well as large scales in space.

Grigory Nikulin (IRF-K), Internal-gravity and Rossby waves.

Motivations for this seminar came from the Geophysical and
Environmental Fluid Dynamics summer school (Department of Applied
Mathematics and Theoretical Physics, University of Cambridge) which I
visited in September. Internal-gravity and Rossby waves are common
waves in oceans and the atmosphere but have different restoring forces
and scales. The restoring force for Rossby waves is the variation with
latitude of the Coriolis force while for internal-gravity waves it is
the gravity force. In the atmosphere these waves transfer momentum
from the troposphere to the stratosphere and mesosphere influencing
the atmospheric circulation on different temporal and spatial scales.
I will give a theoretical background for both kinds of waves in
combination with very good visualizations from laboratory experiments
and computer demonstrations that I have done in the summer school.

Prof. Syun-Ichi Akasofu (International Arctic Research Center, Alaska), Long-standing unsolved problems in solar physics and magnetospheric physics.

Like any field of science, there are a number of long-standing, unsolved problems in solar physics and magnetospheric physics, and their solutions are considered to be almost beyond the capability of the present generation of researchers. However, it is suggested that some of the unsolved problems have remained unsolved because the guiding concepts or paradigms have no sound foundation. In this paper, several paradigms are chosen for examination from this particular point of view. They are sunspots, solar flares/CMEs in solar physics, and the concept of magnetic flux transfer in the magnetosphere. It is obviously not the intent of this paper to provide answers to these difficult problems. Rather, by posing basic questions about the sources of the established paradigms, it is hoped that a new way of approaching the long-standing problems may be opened.

Prof. Sheila Kirkwood (IRF-K), Polar Mesosphere Winter Echoes - new results from statistics and from radar interferometry.

Polar mesosphere Winter Echoes (PMWE) is the name we have given to thin layers of enhanced radar echoes observed by the ESRAD 52 MHz and EISCAT 224 MHz radars from mesospheric heights during winter. Earlier observations of radar echoes from the winter mesosphere were made by the Poker Flat radar and the Alomar Sousy 50 MHz radars during the 1980s. At that time, it was assumed that the echoes were due to layers of turbulence in the neutral atmosphere. Our studies have shown that the radar echo strengths are too high for this explanation to be reasonable. We have further found that they appear at heights where no turbulence is expected (according to co-located meteorological rockets) and where lidars see anomalies in the light-scatter profile. A new statistical analysis of PMWE since 1997 will be reported which shows a substantial increase in PMWE ocurrence. Further, exceptionally strong echoes from 29 October 2003 have been analysed using interferometric methods. Those results show will also be presented.

Tomas Hode (Naturhistoriska riksmuseet), Astrobiology missions to Mars.

The current activity on Mars is in many aspects focused on questions related
to the possibility of past and present life on the red planet, but
investigating conditions for life is not the same thing as actually looking
for fossil or extant life itself. The next generation of Mars landers will
be aimed at investigating evidence for life, but such an endeavour will
require an entirely different setup of instruments, as well as an increased
knowledge of the geological history of Mars. In this talk I will discuss why
life may have existed on Mars, where we should look for it, and how that
search may be conducted in practical terms.

Dr Peter Dalin (IRF-K), Part I. Case study of the role of neutral air turbulence in the PMSE variations. Part II. Concept and technique for the processing of NLC digital photographs.

Part I. There are a lot of theoretical works showing that the neutral air turbulence can play a significant role in the creation of the polar mesosphere summer echoes (PMSE). At the same time the experimental works showed that the turbulence intensities are much too low to produce large radar scatters. On the other hand, some experiments revealed the cases that the regions of maximum radar backscatter correspond to the most unstable phase of gravity wave where the strong turbulence generation takes place. We have found several interesting cases supported the latter phenomenon. The regions of gravity wave propagations and strong wind shears (dynamical instability) coincide with the PMSE enhancements. It is clear that the neutral turbulence is not a dominant factor in the formation of PMSE layers, but the strong turbulent activity can certainly modulate the strength of radar signal on the pre-existing PMSE layers.

Part II. In the second part of my presentation I am going to talk about developing a concept and technique for the processing of digital photographs of noctilucent clouds (NLC). Up to now there are a lot of digital materials on the NLC appearance. The photo-registration of NLC can provide useful information on NLC characteristics, on the gravity and planetary wave activity in the mesopause. But at the same time there is absolutely no both a strategy and technique how to process the photos, to extract the parameters of noctilucent clouds and wave characteristics. I suggest the first version of a new concept and technique on the statistical research of noctilucent clouds with digital photographs.

Andreas Ekenbäck (IRF-K), Using the Flash code for MHD simulations - description of a testcase.

The seminar will describe the open source project FLASH and modifications done to the Flash code which make it possible to use it as an MHD simulation tool. The Flash code is a parallel application, written mainly in Fortran90, developed at University of Chicago. It uses the PARAMESH library to implement an adaptive computational grid. To investigate the possibility of using the Flash code as a general MHD simulation tool, a test case - the interaction between the solar wind and a comet - has been implemented and the seminar will present this implementation and the results therefrom. The possibility of generalizing the simulations to any object in the solar system will also be discussed.

Dr Yoshifumi Futaana (IRF-K), Energetic Neutral Atoms around Mars - Latest results from NPD on board Mars Express.

Energetic natural atoms (ENAs) around Mars are generated by interaction between the solar wind and the Martian exosphere. However, because the ENAs generated by the charge exchange of the solar wind protons have the same velocity as the solar wind flow, most of the ENAs are crashed into the Martian atmosphere. Several generation mechanisms of ENAs in space around Mars have been proposed. We devote our attention to the following two mechanisms: backscattered ENAs and subsolar ENAs.

The backscattered ENAs are generated at the top of the dayside exosphere, where the solar wind protons collide with the exospheric neutral particles and are scattered back as neutral atoms. The flux of the backscattered ENAs is expected to have solar zenith angle (SZA) dependence.

The subsolar ENAs are generated at around the subsolar point, where the solar wind flow is highly deflected from the Sun-Mars line. This means that a part of the deflected solar wind flow would experience charge-exchange and generated ENAs have different velocity of the undisturbed solar wind. The flow of the subsolar ENAs is expected to be an intense beam.

The Neutral Particle Detector (NPD) on board Mars Express obtains data around Mars from the beginning of this year (2004). We analyzed the data of NPD obtained in May and June and found the above-mentioned characteristics in the data. The observations and analysis are reported and the generation mechanisms of the Martian ENAs are discussed in this seminar.

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Spring Semester 2004

22 January (Aula) Dr Uwe Raffalski (IRF-K), Odin’s future: STEAM ? - A new Swedish Satellite for the Investigation of Earth’s Atmosphere. [Abstract]

27 January (Tues.)

Dr Georgy Zastenker (Space Research Institute, Moscow), Review of some new solar wind features investigated by Interball project. [Abstract]

19 February Dr Masatoshi Yamauchi (IRF-K), Wedge-like structured sub-keV ions inside the ring current region. [Abstract]
26 February (Aula) Prof. Rickard Lundin (IRF-K), Solar wind removal of volatiles from celestial objects - perspectives on the Mars Express- and Rosetta missions. [Abstract]
4 March Dr Alexander Kozlovsky (Sodankylä Geophysical Observatory), Response of Dayside Auroras and Ionospheric Plasma Flows to a Solar Wind Pressure Pulse. [ Abstract]
10 March (Wed.) Dr Alexander Zakharov (IKI, Moscow), The PHOBOS-SOIL Project - Phobos Sample Return Mission.
11 March Dr Edmond Murad (Air Force Research Laboratory, USA), Melting and Evaporation of Meteoroids. [Abstract]
25 March Dr Evgenia Belova (IRF-K), Polar Mesosphere Summer Echoes and ionospheric heating: results and future plans. [Abstract]
15 April Dr Vladimir Safargaleev (Apatity), The objectives and some preliminary results of EISCAT campaign on investigation of dayside auroras dynamics. [Abstract]
22 April Dr Yasuhide Hobara (IRF-K), High Altitude Oxygen Outflow Observed by Cluster Satellites: Energization and Subsequent Wave Activities (Preliminary Results). [Abstract]
12 May (Wed.) Sachiko Joko (IRF-K), The relations between geomagnetic activities and O+ outflows observed in the dayside magnetospheric polar region by Cluster/CIS (reversion of ICS-7 presentation). [Abstract]
24 May (Mon.), 11 am Grigory Nikulin (IRF-K), The Mean Meridional Circulation and Wintertime Ozone Buildup in Midlatitudes. [Abstract]
27 May Johan Arvelius (IRF-K), Simulations of a molecular sieve adsorption efficiency (DESCARTES).
3 June Postponed Dr Tima Sergienko (IRF-K)
10 June Dr Herbert Gunell (IRF-K), Solar wind charge exchange at Mars. [Abstract]

Abstracts

Dr Uwe Raffalski (IRF-K), Odin’s future: STEAM ? - A new Swedish Satellite for the Investigation of Earth’s Atmosphere.

The Odin satellite was launched on 20 Feb 2001 into a near polar orbit and is fully operational since. On 15 orbits a day measurements of a large number of trace gas constituents between 8 and 100 km are performed covering the latitude range 82°S to 82°N (in atmospheric mode). In astronomical mode it studies the physics and the chemistry of the interstellar medium by observing emission from key species. Odin is a Swedish-led mission in co-operation with Canada, Finland and France using sub-mm spectroscopy for astronomical and atmospheric studies. This is the first time sub-mm frequencies have been used from space for such studies. Earlier instruments such as the MLS instrument on NASA's Upper Atmosphere Research Satellite (UARS) and the MAS instrument on the Space Shuttle operated at mm-wave frequencies which limits their sensitivity and height resolution for a given antenna size. In addition to the Sub-mm Radiometer (SMR), an Optical Spectrometer and Infrared Imaging System (OSIRIS) is included in the payload to complement and enhance the atmospheric studies. OSIRIS is one of the first limb viewing spectrometers operating in scattered light.

The status of Odin is better than ever. However, even Odin will eventually die and new projects are coming up all the time. In 2002 the Swedish National Space Board sent out a call for ideas for future satellites and space missions. This led to a project called STEAM (stratosphere-troposphere exchange and monitoring), which received highest priority at SNSB. If this project gets funding this satellite will proceed the monitoring tasks of Odin. But it will also address scientific questions like the exchange of gases between the upper troposphere lower stratosphere region. Most important will be the water vapor transport which has significant importance on the future climate.

In my talk I will present the achievements with Odin as well as the ideas that make STEAM such an interesting project for the Swedish space activities.

Dr Georgy Zastenker (Space Research Institute, Moscow), Review of some new solar wind features investigated by Interball project.

Some new features of the solar wind were found in the INTERBALL project by comparison of the multipoint observations and using high-resolution plasma measurements onboard INTERBALL-1/MAGION-4 satellites. These results allow us to suggest some new concepts about solar wind in several points, namely:
- dimensions and persistent time of the middle-scale structures,
- large and very sharp plasma density changes on the borders of the small-scale structures,
- significant inclinations of many sharp plasma phase fronts,
- geoeffectivity of the sharp changes of the plasma dynamic pressure,
- not only magnetic field but also plasma in phase fast variations in the foreshock,
- large amplitude, low and high frequency plasma and magnetic field variations in the magnetosheath; their origin, dependence on IMF direction and comparison with MHD models.

Dr Edmond Murad (Emeritus, Space Weather Center of Excellence, Air Force Research Laboratory, Hanscom AFB, MA, USA), Melting and Evaporation of Meteoroids.

Meteors are by definition transitory phenomena arising from the entry of meteoroids in the Earth’s atmosphere. The meteoroids are small particles generally arising from the dust released by comets as they near perihelion. The dust, for the most part consists of silicates, some organic matter, and some water; the dust is released into a very cold environment (< 100 K), even though the temperature of the comet nucleus at perihelion may be as high as 330 K. As the orbit of the dust cloud intersects that of Earth, some of the dust is captured by Earth. The captured dust begins its fiery descent into Earth’s atmosphere, giving rise to the shooting star phenomenon. The shooting star phenomenon indicates that the temperature of the meteoroid is quite high – somewhat resembling an incandescent lamp. At that point most of the meteoroid material is evaporated. Between the point of capture and early descent into the atmosphere (say ~ 200 km) and the evaporation (when the meteoroid is incandescent) of the metals, a complex set of chemical processes occurs, despite the short transit time. I will talk during this seminar about phase transitions undergone by the dust material, eventual melting, and evaporation (or sublimation of the metals). I will briefly discuss how fractionation and possible formation of eutectic mixtures might affect the observed metallic species.

Dr Masatoshi Yamauchi (IRF-K), Wedge-like structured sub-keV ions inside the ring current region.

Structured dispersive sub-keV ions inside the ring current region (L=3 to 10), so called wedge-like dispersions, are surveyed using Viking, Freja, Munin, and Cluster satellites.
(1) What is the signatue, and why they are interesting (to me)?
(2) Patterns classification and statistics.
(3) Comparison to past simulation (based on long-time drift by ExB and grad-B drifts).
(4) correlation to the geomagnetic activity (past 12 hours).
(5) problems/puzzles (identification, composition, LT distribution,
substorm relation).

Prof. Rickard Lundin (IRF-K), Solar wind removal of volatiles from celestial objects - perspectives on the Mars Express- and Rosetta missions.

The Mars-Express and the upcoming Rosetta-missions are two important ESA-missions with major IRF involvement, scientifically as well as technically. A key science objective for both missions is to understand the evolution of celestial bodies in the solar system, in particular the question about source and loss mechanisms for volatiles. The solar wind interaction with the atmosphere/ionosphere of the Earth-like planets and comets represents an important loss process. The Earth-like planets, orbiting close to the Sun, are subject to a continued forcing by solar radiation - electromagnetic as well as corpuscular. Comets are in a similar manner subject to strong forcing during their perihelion passes. The solar forcing leads to escape of matter from the celestial objects by thermal (Jeans) escape and non-thermal (plasma) escape processes. The visible evidence for the erosion of matter from a comet is the long tail, specifically the plasma tail (ion tail). Thermal and non-thermal escape are both important, but non-thermal escape is more efficient as a loss process.
ASPERA on Mars Express will address new aspects of the non-thermal escape processes (ENA-imaging) but it will also enable a follow-up of our Phobos-2 findings on the "planetary wind" (plasma escape) from 1989. Moreover, ASPERA may or may not corroborate some controversial findings obtained from Phobos-2 (e.g. dusty plasma).
On board the Rosetta space probe, scheduled for launch on 26 Feb 2004, we have two IRF instruments, ICA (ion composition analyzer) and LAP (Langmuir probe), with the prime objective to study the solar wind interaction with comet 67P/Churyonov-Gerasimenko.
The escape of matter from a celestial body by non-thermal escape can be modelled from relatively simple energy and momentum considerations. We use Mars and 67P/Churyonov-Gerasimenko as typical targets for the solar wind energy and momentum exchange and compute the model escape of volatiles as a consequence of this interaction. The results from the model is interesting, indicating that solar wind erosion is sufficient in explaining the major erosion from non-magnetized objects in the inner solar system.

Key words: Solar wind, the atmosphere of planets and comets, plasma escape

Dr Alexander Kozlovsky (Sodankyla Geophysical Observatory, Finland), Response of Dayside Auroras and Ionospheric Plasma Flows to a Solar Wind Pressure Pulse.

Global ultraviolet auroral images from the IMAGE satellite are used to investigate the response of the dayside auroral oval to a sudden impulse (SI) in the solar wind pressure. The observations are supplemented by the TV all-sky camera images over Svalbard in the pre-non sector. We show that after the SI, new discrete auroral forms appear in the poleward part of the auroral oval so that the middle of the dayside oval moves poleward from about 70 to about 73 deg. AACGM latitude. This poleward shift started in the 15 MLT sector, then similar shift was observed in the MLT sectors located more westerly, and eventually the shift was seen in the 6 MLT sector. Thus, the auroral disturbance "propagates" westward (from 15 MLT to 6 MLT) at an apparent speed of the order of 7 km/s. We show that the above auroral disturbances are associated with the westward propagating convection vortex as inferred from the global convection maps produced by the SuperDARN HF radars. The poleward boundary of the auroral oval did not show any prominent motion associated with the SI. The optical and radar observations can be interpreted in terms of the pressure disturbance propagation through the magnetosphere at a velocity of the order of 200 km/s that is essentially slower than a magnetosonic (fast Alfvén) wave, and generation of a potential (curl-free) electric field in the wake of the disturbance. We suggest that the interchange instability is a possible reason for the development of discrete dayside auroral forms after the SI. We discuss the reasons for the slow propagation speed of the disturbance and for a vortex-like convection pattern associated with the auroral motions.

Dr Vladimir Safargaleev (Apatity), The objectives and some preliminary results of EISCAT campaign on investigation of dayside auroras dynamics.

The EISCAT experiment on study the dayside auroras over Svalbard was performed on 19-27 January 2004. Participants: Swedish Institute of Space Physics, Kiruna, Sweden (H Nilsson, T Sergienko), Sodankylä Geophysical Observatory, Oulu University, Oulu, Finland (A Kozlovsky), Polar Geophysical Institute, Apatity, Russia (V Safargaleev). We used ESR-32m antenna (pointed to west at 45 deg. elevation) to measure the plasma flow along East-West, and mainland UHF radar was pointed to north at low elevation (20 deg.) to observe the North-South plasma flow. The auroral activity was monitored by the PGI TV camera in Barentsburg and the FMI ASC camera in Longyearbyen. The data of the PGI induction magnetometer allowing the registration of magnetic field variations in the range of 0.1 ˆ 20 Hz were also available. Three intervals of auroral activity will be discussed: an auroral "torch" formation, the poleward displacement of auroras after IMF Bz turning northward and the PMAF event accompanying with electron density enhancement in EISCAT data and "pearl" type magnetic pulsations in magnetometer data. The possible interpretation will be suggested.

Dr Evgenia Belova (IRF-K), Polar Mesosphere Summer Echoes and ionospheric heating: results and future plans.

Polar mesosphere summer echoes (PMSE) are very strong radar returns that occur during summer months near the mesopause at high latitudes. They were discovered about 20 years ago. It seems that PMSE reflect complicated processes occurring in a multi-component plasma consisting of electrons, ions and charged aerosols and interaction between ionized and neutral atmospheric components. So far there is no clear and complete understanding the mechanism of PMSE. In order to influence the electron component during PMSE events, we conducted, in the summers of 1999, 2001, 2002 and 2003, joint PMSE/Heating experiments using the EISCAT VHF radar and the EISCAT Heating facility.
I will give a review of these PMSE and ionospheric heating experiments. Obtained results will be discussed and future plans will be presented.

Dr Yasuhide Hobara (IRF-K), High Altitude Oxygen Outflow Observed by Cluster Satellites: Energization and Subsequent Wave Activities (Preliminary Results)

Cluster spacecrafts observe high altitude ion outflow events rather frequently. In this report, we concentrate on one ion outflow event with a significant energization of oxygen ions in concert with Broad-band ELF emissions in April 2001 to study the relationship between high-altitude heavy ion energization and subsequent wave activities.
The outflow events are observed by two S/Cs for which CIS-CODIF measurements are available at high altitude polar cap region around 7.5 Re. The separation distances between the S/Cs are a few hundreds km. The energy spectrogram of oxygen ions shows an increase of their energies up to a few tens of keV from hundreds of eV within 30 seconds and wave equipments (EFW and STAFF) detect enhanced wave activities in the ULF/ELF range. During this event, hydrogen ions do not show the meaningful heating. Comparative analysis of temporal variations between particle characteristics (distributions, temperature, moments, energy flux etc) and wave properties (such as wave normal angle, polarization, and Poynting flux calculation) for three S/Cs will be performed to investigate the source mechanism and spatio-temporal characteristics of the oxygen ions and subsequent wave activities.

Dr Herbert Gunell (IRF-K), Solar wind charge exchange at Mars.

Wherever the solar wind meets a neutral atmosphere, X-rays are emitted by a charge exchange process between the neutrals and heavy solar wind ions.

A hybrid simulation of the solar wind-Mars interaction and a test particle simulation of heavy ion trajectories near Mars is used to compute the contribution from charge exchange processes to the X-ray emission from Mars. The results are compared to observations of X-rays from Mars made with the Chandra telescope (Dennerl, K., Astronomy & Astrophysics, vol. 394, pp. 1119-1128, 2002). The comparison indicates that the solar wind charge exchange process is a likely candidate for the production of the X-ray halo at Mars.

The calculations were performed in three steps. First the solar wind parameters were estimated from data obtained by the WIND spacecraft. Since Mars was near opposition the plasma that was sampled by WIND near the earth on 2 July 2001 arrived at Mars two days later during the X-ray observation. The data was scaled with the distance from the sun, and the average parameter values over the period of the observation were used as input parameters for a hybrid simulation.

The second step was running a hybrid simulation of the interaction between the solar wind and Mars to obtain the electric and magnetic fields around Mars.

As a third step a test particle simulation was run, calculating the trajectories of heavy solar wind ions in the electric and magnetic fields that were obtained from the hybrid simulation. The X-ray emission density was saved on a grid for each time step of the test particle simulation. A hundred thousand trajectories were calculated for each of ion species.

Sachiko Joko (IRF-K), The relations between geomagnetic activities and O+ outflows observed in the dayside magnetospheric polar region by Cluster/CIS (reversion of ICS-7 presentation).

The terrestrial-origin O+ ions outflowing in the dayside
high-altitude (from 3Re up to 11Re)/-latitude (from 70 to 90
degrees in invariant latitude, ILAT) polar region have been
observed by the CIS instrument onboard the Cluster satellite.
The statistics of polar outflowing O+ ions ((1) energy of max
number flux, (2) max number flux, and (3) number density) is
complied in terms of geomagnetic activities represented by
Kp index for global/planetary geomagnetic activity and ASY/SYM
indices for mid-latitude geomagnetic disturbances (instead of
AE and Dst).
It seems that O+ ions outflowing in the polar region respond
well to ASY/SYM indices rather than to Kp on (2) and (3)
according to on-going study.

Grigory Nikulin (IRF-K), The Mean Meridional Circulation and Wintertime Ozone Buildup in Midlatitudes.

Vertical residual velocities calculated from the quasigeostrophic
transformed Eulerian mean thermodynamic and continuity equations are used to study connections between the residual mean circulation of the stratosphere and wintertime midlatitude ozone buildup. We found agreement with theoretical considerations for November, January and February while there are no expected connections in December. Difference between months may be explained by stronger contributions from other processes (meridional mixing, chemistry) than the residual mean circulation.

Also I will explain theoretical background for calculations of mean meridional velocities.


Autumn Semester 2003

Tues. 2 September

Prof. Amos Zemel (Ben Gurion University of the Negev, Israel), Innovative Renewable Energy Research in Israel: From Large Scale to Small Scale and Back. [Abstract]

11 September

Prof. Dr Ingrid Mann (Institut für Planetologie, Westfälische Wilhelms-Universität, Germany), The Heliosphere and the Meteoritic Complex. [Abstract]

18 September

Prof. Bengt Hultqvist (IRF-K), Downward Accelerated Ions: Acceleration Mechanism and Ion Source. [Abstract]

25 September

Prof. Rickard Lundin (IRF-K), Plasma in the magnetospheric boundary layers: Frozen in - or not? [Abstract]

2 October

Magnus Emanuelsson (IRF-K), Strålningstest av OpAmpar. [Abstract]

Mon. 13 October, 10 am (Aula)

Dr Evgenia Belova (IRF-K), How and why we heat the ionosphere. (Docent lecture)

16 October, 10-12 (Aula)

Spatial Modelling Centre (SMC), Umeå University: Presentation of the database ASTRID, the micro-simulation model SVERIGE, and related projects. [Abstract]

23 October

Dr Mats Holmström (IRF-K), Monte Carlo simulations of planetary ions and neutrals at Mercury. [Abstract]

30 October

Grigory Nikulin (PhD student, IRF-K), Influence of early winter wave activity on midwinter circulation in the stratosphere and troposphere. [Abstract]

6 November

Dr Yasuhide Hobara (postdoc, IRF-K), Extremely low frequency radiation and ionospheric disturbances in association with transient luminous events in the mesosphere. [Abstract]

13 November

Dr Peter Dalin (IRF-K), The comparison of Danish and Moscow NLC observations: statistical results. [Abstract]

20 November

Dr Hans Nilsson (IRF-K), Radar Observations in the Vicinity of Pre-noon Auroral Arcs. [Abstract]

4 December (Aula)

Walter Allvin (Zero Group) presents Xero and the Zero Group's activities (in the Aula): www.xero.se

11 December

Dr Tima Sergienko (IRF-K), The lateral spread of proton precipitation: A comparison between incoherent scatter radar observations and model. [Abstract]

ABSTRACTS

Professor Amos Zemel (Ben Gurion University of the Negev, Israel), "Innovative Renewable Energy Research in Israel: From Large Scale to Small Scale and Back."

Renewable energy research carries a long tradition in Israel. It is strongly
associated with the name of Dr. Harry Zvi Tabor, the solar energy pioneer who, back in the 50's, introduced and promoted the concepts of selective coatings, the solar pond (based on the idea originated by R. Bloch) and participated in the development of the Organic Rankine Cycle turbine. These concepts have now turned classical, and evidence of solar energy at
work is apparent on the rooftop of every Israeli house by the obligatory domestic solar hot water systems. While intensive R&D efforts in Israel continue to advance nearly every aspect of solar energy research, my aim here is to present some of the most exciting approaches that are being investigated. Not all of the systems described here have reached the stage of commercialization. Yet, if they stand up to expectations, some may revolutionize the way we think about solar energy and use it for the benefit of mankind. In order to illustrate the wide scope and diversity of these novel ideas, the systems are classified according to their scales - from very large dishes and central receivers through mini-dishes to the molecular structure of novel PV materials - and back to the gigantic "energy towers" that involve the highest structures ever built by human beings.

Prof. Dr Ingrid Mann (Institut für Planetologie, Westfälische Wilhelms-Universität, Germany), "The Heliosphere and the Meteoritic Complex."

The near-solar cloud inside Earth orbit is the central region of the meteoritic complex that evolves from the small bodies of our planetary system. With its complexity of acting forces, physical processes, and interactions, it provides a unique opportunity for directly studying a cosmic dust-plasma cloud and processes therein that also appear in other cosmic environments. Dust particles produce the solar F-corona and the zodiacal light and sun-grazing comets are observed falling into the Sun. Yet, these astronomical phenomena reveal only a part of the dust physics in the inner solar system. Dust charging, surface reactions and dust destruction are not accessible to direct observations. The production of pick-up ions provides the connection of the meteoritic complex to other populations of heliospheric particles. Recent observations from spacecraft open up new possible scenarios as to the sources and composition of meteoritic material in the inner solar system.

Prof. Bengt Hultqvist (IRF-K), "Downward Accelerated Ions: Acceleration Mechanism and Ion Source."

First, a summary of the observations of downward accelerated ions with keV or sub-keV energies at altitudes of about 1700 km is given and the mechanism causing the accelerating quasi-static potential difference is described. Thereafter it is shown that the ionospheric ions may be transported upward through the potential region in a process sometimes called the 'pressure-cooker' mechanism involving wave turbulence within the region. The turbulence also gives rise to pitch-angle scattering of the ions so that a fraction of them are precipitated into the altitude range where they are observed by the satellite. This process gives the observed spectral characteristics of the accelerated ions.

Prof. Rickard Lundin (IRF-K), "Plasma in the magnetospheric boundary layers: Frozen in - or not?"

The notion Frozen-in Magnetic Field-Lines originates from Hannes Alfvén, a result of a work on electromagnetic-hydrodynamic waves published in 1942 that rendered Alfvén the Nobel prize in Physics in 1971. Frozen.in magnetic field, or ideal MHD, IM, has subsequently become widely used in space plasma physics - misused according to the inventor himself. The debate on the applicability of IM started in the late 1950:ies and has basically continued ever since. The debate is not about the limitations of IM, these are relatively well understood. Magnetic reconnection, the "fusing" of magnetic field lines, is an example of a microscopic process where ideal MHD is locally violated. However, it is then also assumed that the local violation will not affect the macrostructure. IM is assumed to hold on an overall basis regardless of microphysical exceptions.

The issue is therefore to determine directly from plasma measurements whether IM holds on a large-scale basis - or not. One crucial aspect is to test whether E = - vxB, i.e. the plasma drift is determined by the electric field. Yet another is to test whether the change in magnetic flux (dB/dt) equals the rotation of vxB (rot(vxB)). In this report I will present Cluster CIS-data showing when IM applies and when it does not. I will also give a study report on a way to determine an IM-index from space plasma data.

Magnus Emanuelsson (IRF-K), "Strålningstest av OpAmpar."

På seminariet avhandlades:
- Hur målsättningen med resan var att öka IRF-K:s kunskaper om stråltester i Uppsala, och dessutom utvärdera både mätmetoder och komponenter.
- Vilka resurser som finns att tillgå hos IRF-U och The Svedberglaboratoriet i Uppsala.
- Vilka instrument, vilken testmetod och vilken uppkoppling som användes i stråltesten.
- Testresultat för operationsförstärkarna LMC6484, AD704, AD713.
- Vilka erfarenheter vi fått av resan och testerna och hur dessa kan förbättras.
- Vad mer vi vill testa framöver.

Spatial Modelling Centre, Umeå University, "Presentation of the database ASTRID, the micro-simulation model SVERIGE, and related projects."

After a short presentation of SMC, we will inform you about our demographic database ASTRID. This database is one of the most important sources for all research performed at SMC.

The main project, that more or less all the other projects are connected to, is the micro-simulation model SVERIGE. We can simulate the lives of 10 million citizens in Sweden where everyone on a yearly basis is exposed to the possibility of various life events happening.

The life events in SVERIGE are divided into different modules. The modules that affect the demography are fertility, mortality, emigration and immigration. In addition there are modules concerning family structures such as leaving home, finding a partner and forming a new family (cohabiting), marriage and divorce. In SVERIGE everyone is educated to different degrees, they can get a job and a salary. All these modules are connected and they influence each other dynamically. It is possible to simulate the life of 10 million people in about one and a half minutes per year.

We will also mention some other simulation projects such as KINA, LISA and Transmission of infections in Sweden.

To run such large models it is necessary to develop techniques so that the computer can handle all the agents and their variables in an acceptable time. We will inform you of how we handle this technically.

Lastly we will give you a short introduction to subprojects such as Long-distance commuting, Mortality related to weather situations and climate, Mortality related to distance to care, Tourism and regional development, Tourism in protected national areas, and Employment, labour market and regional development.

Dr Mats Holmström (IRF-K), "Monte Carlo simulations of planetary ions and neutrals at Mercury."

Very low energy neutral atoms (VLENA) at Mercury are produced at the surface by photon stimulated desorption, micro meteoroid vaporization, sputtering (from precipitating neutrals and ions) and thermal release. Also, charge-exchange is a source. The loss processes are, surface precipitation, photoionization and charge-exchange.

We have studied the production of photoions at Mercury using a Monte Carlo model, and have computed distribution functions and precipitation maps for photoions produced from several neutral species, such as O and Na. Using the computed precipitation maps, the amount and morphology of sputtered neutrals, due to precipitating photoions, can be estimated. Among other things, it is found that photoions can be accelerated to high energies before impacting the planetary surface, e.g., several keV for oxygen.

Grigory Nikulin (PhD student, IRF-K), "Influence of early winter wave activity on midwinter circulation in the stratosphere and troposphere."

Using NCEP/NCAR reanalysis data we show that the November-December averaged stratospheric eddy heat flux is strongly anticorrelated with the January-February averaged eddy heat flux in the midlatitude stratosphere and troposphere. This finding further emphasizes differences between early and midwinter stratospheric wave activity behavior, which have recently been found in long-term variations. Our analysis suggests that this anticorrelation results from changes in wave activity generation in the troposphere. Stronger (weaker) wave activity in early winter leads to weaker (stronger) wave activity generation in the troposphere during midwinter. We show also that enhanced equatorward wave refraction during midwinter that is due to the stronger polar night jet, is associated with weak wave activity in the early winter. It is suggested that the effect of enhanced midwinter wave activity generation in the troposphere in the years with weak early winter wave activity overcompensates the effect of increased equatorward wave refraction in midwinter, leading to a net increase of the midwinter wave activity flux into the stratosphere.

Trends are opposite in early- (positive) and midwinter (negative) wave activity for the 1979-2002 period. However, the early winter trends are at the edge of statistical significance and very sensitive to the choice of period in contrast to the midwinter trends.

Dr Yasuhide Hobara (postdoc, IRF-K), "Extremely low frequency radiation and ionospheric disturbances in association with transient luminous events in the mesosphere."

TLEs (transient luminous events) in the mesosphere like red sprites and elves were observed over the sea of Japan during the thunderstorm activity in the wintertime. We analyze quantitatively the results from coordinated measurements consisting of ELF (extremely low frequency) electromagnetic radiation, VLF (very low frequency) subionospheric disturbances, and lightning discharges associated with these optical events. We found a clear relationship between vertical charge moment change calculated from ELF observation and the ionospheric disturbances regardless of the types of optical events. This indicates significant atmosphere-mesosphere-ionosphere coupling. Sprites tend to associate with large ionospheric disturbances (-13 to +4.6 dB) with a large vertical charge moment change, whereas a large lightning peak current (+223 to 479 kA) leading to the strong EMP (electromagnetic pulse) is necessary to initiate elves, but with rather small ionospheric disturbances.

Dr Peter Dalin (IRF-K), The comparison of Danish and Moscow NLC observations: statistical results.

P. Dalin, S. Kirkwood, H. Andersen, O. Hansen, V. Romejko

Systematic NLC observations conducted in Denmark and Moscow during the period 1983-2002 are compared and statistical results both for seasonally summarized NLC parameters and for individual NLC appearances are described. Careful attention is paid to the weather conditions in each NLC case. This turns out to be a very important point both for NLC case study and for correlation analysis of average values. Time series of seasonal values show rather good similarity (taking into account the weather conditions) but, at the same time, the comparison of individual cases of NLC occurrence reveals substantial differences.

Dr Hans Nilsson (IRF-K), Radar Observations in the Vicinity of Pre-noon Auroral Arcs.

A combination of EISCAT incoherent scatter radar observations, FMI Longyearbyen allsky camera observations, IMAGE magnetometer chain data and Polar spacecraft data has been used to study pre-noon dayside auroral arcs. The studied arcs are mainly related to the shear region between the morningside eastward flow (the return flow region) and the shielded, corotating plasma. These arcs thus appear on closed field-lines, though they still show mainly poleward motion similar to poleward moving auroral forms. The EISCAT Svalbard radar data allow us to study in some detail the plasma in and surrounding the arcs and in particular the morpholgy of the transverse electric field associated with the arcs. It turns out that the arcs are associated with a strong transverse electric field on the poleward side, consistent with post-midnight nightside observations. The appearance of the arcs studied in detail is associated with enhancements of the electric field in the equatormost part of the eastward flow region. Electric field and arc intensifications occur on a 3-5 minute time scale. The interchange instability is discussed as a plausible source process for the arcs. The source plasma population is studied using Polar data. Polar electron data is also used as input to a model, and the model results are compared to the EISCAT and all-sky camera observations. Agreement is found to be very good in the diffuse aurora.

Dr Tima Sergienko (IRF-K), The lateral spread of proton precipitation: A comparison between incoherent scatter radar observations and model.

Incoherent scatter radar (EISCAT) observations of the quiet time evening sector ionosphere show a very smooth equatorward border of the region of enhanced ionization associated with the diffuse auroral precipitation. Conjugate satellite observations show that the equatormost diffuse aurora typically consist of proton precipitation only. Furthermore, a rather sharp equatorward cut-off of the proton precipitation is observed. The difference between the radar and satellite measurements is expected to be due to charge exchange spread of the protons. A comparison between the satellite and radar data thus allows for an unprecedented observation study of the charge exchange spreading effect. The satellite (DMSP) data are used as input to a model of the electron and proton transport into the atmosphere based on Monte Carlo simulations. The agreement is found to be very good.

[TOP]


Spring Semester 2003

16 January

Sven Bugarski (University of Heidelberg), Methods and Problems of BrO DOAS Analysis. [Abstract]

7 February

Mats André (IRF Uppsala), Layers at ion and electron scales in the high-latitude magnetopause.

11 February

Dr Takumi Abe and Dr Takeshi Imamura (Japan), Japanese Venus Climate Orbiter.

13 February

Evgenia Belova (IRF-K), A Study of Polar Mesosphere Summer/Winter Echoes with the EISCAT VHF Radar. [Abstract]

20 February

Vladimir Safargaleev (Polar Geophysical Institute, Apatity, Russia), High-latitude dayside Pc1 events as indicator of reconnection. [Abstract]

27 February

Rickard Lundin (IRF-K), The Wakes and Magnetotails of Venus and Mars. [Abstract]

13 March

Grigory Nikulin (IRF-K), Dynamical contributions to the total ozone trends in the Northern Hemisphere midlatitude. [Abstract]

20 March, 1 p.m.

Sheila Kirkwood (IRF-K), Dust in the mesosphere - is it really there and why should we care? [Abstract]

27 March

Susanne Roslin (Umeå University), Adsorbtion of CFC on Carboxen during sampling in the stratosphere. [Abstract]

3 April

Peter Dalin (IRF-K), The observation of gravity waves in Noctilucent Clouds. [Abstract]

10 April, 1 p.m.

Asta Pellinen-Wannberg (IRF-K), The EISCAT meteor method: a review and recent results. [Abstract]

Tues. 22 April, 10 a.m.

Hans Nilsson (IRF-K), Cluster multi-point observations of ion outflow. [Abstract]

8 May

No seminar (Rymdforum 03 conference in Kiruna)

15 May

Csilla Szasz and Johan Kero (IRF-K), A Solar Active Region Quasi-Biennial Fluctuation. [Abstract]

22 May

Sachiko Joko (IRF-K), Ion velocity distributions at higher altitudes observed by CIS/Cluster: Formation of shell-like distribution as observed in cometary pick-up ions? [Abstract]

5 June

Jane Zheng-Johansson (IOFPR, Nyköping), Unification Scheme for Classical and Quantum Mechanics at All Velocities. [Abstract]

12 June

Herbert Gunell (IRF-K), Simulated ENA images of the Venus-solar wind interaction region. [Abstract]

19 June

Tima Sergienko (IRF-K), Quenching rates of O(1D) in the upper thermosphere. [Abstract]


ABSTRACTS

"Methods and problems of BrO DOAS analysis", Sven Bugarski (IRF-K)

The focus of the seminar will be the DOAS (Differential Optical Absorption Spectroscopy) measurements from the University of Heidelberg at IRF. I will briefly describe the involved instruments, explain the methods to calculate SCDs (slant column densities) of trace gases and discuss problems, results and aims of my work.

"A Study of Polar Mesosphere Summer/Winter Echoes with the EISCAT VHF Radar", Evgenia Belova (IRF-K)

I will tell about use of EISCAT VHF radar in studies of mesospheric layers which occur in summer and winter time. My report is based on the presentations given on the last COSPAR conference in Houston, USA in October 2002. The abstracts of these presentations are below:

STUDY OF POLAR MESOSPHERE WINTER ECHOES DURING SOLAR PROTON EVENTS WITH THE EISCAT VHF RADAR

E. Belova (1), S. Kirkwood (1), M. Rietveld (2, 3), I. Häggström (3)
(1) Swedish Institute of Space Physics, Kiruna, (2) EISCAT Scientific Association, Kiruna, (3) Max-Planck-Institut für Aeronomie, Katlenburg-Lindau

Recently, Kirkwood et al. (2002) reported detecting enhanced MST radar echoes from mesospheric altitudes in the winter period during Solar Proton Events (SPEs). It was proposed to refer to them as Polar Mesosphere Winter Echoes (PMWE). They showed characteristics from which one can conclude that aerosols are most likely involved in generation of the radar echoes, in the same way as for PMSE. It was also found that there is no direct dependence of PMWE occurrence on electron density (calculated using ionospheric modelling). However PMWE occurrence correlates well with low values of l (the ratio of negative ion density to electron density, derived also from the model). Our aim is to check these results by applying a new EISCAT D-layer program during PMWE events. On November 5 and 23, 2001 two strong SPEs occurred. The ESRAD 52 MHz MST radar detected enhanced backscatter from 65-75 km altitude. The EISCAT VHF radar was running the D-layer Common Program. We use electron density profiles derived from incoherent backscattered power to interpolate electron density at the PMWE altitudes. The relationship we obtain between PMWE power and electron density will be presented and discussed.

RELATION BETWEEN POLAR MESOSPHERE SUMMER ECHO POWER AND ELECTRON DENSITY AS MEASURED WITH THE EISCAT VHF RADAR

E.Belova (1), I. Häggström (2), P. Chilson (3), S. Kirkwood (1)
(1) Swedish Institute of Space Physics, Kiruna, (2) EISCAT Scientific Association, (3) Cooperative Institute for Research in Environmental Sciences, University of Colorado, and NOAA Environmental Technology Laboratory, Boulder

Strongly enhanced radar echoes from the polar summer mesopause (PMSE) are an indicator of the complex processes occurring in this important region. They reflect coupling between neutral and ionised atmospheric components, the latter including electrons, ions and charged aerosols. The dependence of PMSE power on background electron density has been discussed in several papers. Electron density values used for such studies have been derived from model simulations, or proxies such as riometer data have been used to estimate electron density at mesospheric altitudes. Reliable rocket measurements of electron density are available only for a small number of cases. They are not sufficient to make a firm conclusion either on the dependence of PMSE power on electron density or on electron density limits for the existence of these strong echoes. The latter may be crucial for testing existing PMSE theories. We propose to use a new D-layer EISCAT Common Program (CP) for deriving electron density and other ionospheric parameters just below and above the layers with abnormally enhanced power. Values of background electron density at altitudes of PMSE can be calculated using interpolation. In summer 2002 a PMSE experiment will be conducted in Northern Norway using the EISCAT VHF radar. It will be run in 2 modes: the D-layer CP and Special Program (SP). The SP is designed to detect and to measure PMSE power. By running the D-layer program for 24 hours we expect to cover a wide range of electron density values. The first results of this experiment will be presented. The relationship we obtain between PMSE power and electron density will be discussed.

[TOP]

"High-latitude dayside Pc1 events as indicator of reconnection", Vladimir Safargaleev (Polar Geophysical Institute, Apatity, Russia)

The data of induction magnetometer installed at Barentsburg observatory in Spitsbergen archipelago are analyzed in combination with the data of two other magnetometers located on Scandinavian and Kola Peninsulas. We considered the intervals of very large negative IMF Bz when the cusp is assumed to be shifted at large distance south of its statistical position and Spitsbergen turns out in the polar cup.
Altogether, eight intervals were considered. In all cases the DMSP data indicated that Barentsburg observatory was in the polar cap, whereas the location of two others might be associated with either cusp or llbl or bps projections. The magnetic pulsations of Pc1 frequency range were observed around the local noon and in the polar cap only. They had a form of several short-living bursts and lasted for 5 - 15 minutes. In the cases when the CUTLASS data were available, the interval of Pc1 activity coincided well with the appearance and decay of fast ionospheric convection flow channel. We think that these pulsations are originated from the magnetosheath (namely, from the plasma depletion layer) where the plasma is anisotropic and undergoes the IC-instability. Due to impulsive reconnection, the unstable plasma turns out on the magnetic field lines connected with the Earth's ionosphere and IC-waves may be seen on the ground as the bursts of Pc1.

"The Wakes and Magnetotails of Venus and Mars", Rickard Lundin (IRF-K)

R. Lundin and S. Barabash

The solar wind interaction with the weakly magnetized Venus and Mars differs from the solar wind interaction with the Earth and other strongly magnetized planets in our solar system. A significant difference between magnetized and unmagnetized planets is the stand-off distance to the solar wind, the solar wind impacting directly on the topside atmosphere of nonmagnetized planets, whilst a strongly magnetized planet fends off the solar wind well above the atmosphere. In fact, neglecting the difference in gravitational pull, there are many similarities between Mars, Venus and comets in terms of their interaction with the solar wind. However, for the nightside tail region the difference between magnetized and nonmagnetized celestial objects are less marked. Nonmagnetized celestial objects with an atmosphere have, like magnetized objects a magnetotail induced by their interaction with the solar wind.

In this report we review the magnetotails of Mars and Venus and compare with the observational/ visible characteristics of comets. Besides their overall morphology and the general atmospheric outflow/erosion, we also consider the filamentation of ionospheric plasma ejected into the magnetotail from non-magnetized as well as magnetized bodies in the inner part of the solar system.

"Dynamical contributions to the total ozone trends in the Northern Hemisphere midlatitude", Grigory Nikulin (IRF-K)

During last years more and more evidences showing importance of
dynamic processes for the total ozone decline have been presented. A
separation of chemical and dynamical contributions to total ozone
variability is the significant question for understanding of the ozone
changes. Several recent studies have shown that a substantial part of
year to year winter-spring total ozone variations in the Northern
Hemisphere (NH) middle and polar latitudes are influenced by dynamic
factors. Wave activity in the lower stratosphere and different indices
of atmospheric circulation patterns are mostly used as dynamical
proxies. At the same time estimations of dynamical contributions in
the observed long term ozone trends are very different. Partly it
could be explained by different months and periods that have been
taken for investigations.
The multiple linear regression model describing evolution of the NH
midlatitude total ozone during February-May (1979-2001) has been
applied to estimate contributions of atmospheric circulation changes
to the observed long-term trends in total ozone. We use 4 predictors,
namely: the 100 hPa zonal mean heat flux, the Arctic Oscillation index,
the quasi-biennial oscillation and the 11-year solar cycle. The
regression accounts for 77% of the observed total ozone variance in
May, 83% in April, 77% in March, and 76% in February. There are no
significant trends in the model residuals from March to May. The
February residual trend is on the edge of statistical significance and
reduced by more than two times. The obtained results show that the
dynamic factors can play the primary role in the long-term changes of
the NH midlatitude total ozone.

"Dust in the mesosphere - is it really there and why should we care ?" Sheila Kirkwood (IRF-K)

There is a continual rain of extraterrestrial matter into our atmosphere. There are also increasing amounts of material sent up from the Earth's surface (space debris, rocket exhausts). There are theoretical grounds for expecting that this leads to a population of 'dust' in the middle atmosphere, but this dust has not yet been proven to exist. If it does exist, it can have significant consequences for atmospheric composition by introducing heterogeneous chemical reactions. It is also of importance for the interpretation of remote sensing by optical methods - the usual assumption is that there is no dust so that dust layers will be interpreted as something else (e.g. extremely low temperatures or high water content).

In the last 3 years we have found radar echoes with ESRAD and EISCAT which seem to correspond to dust layers. The seminar will be a progress report on how we are building up evidence (using radar, lidar and rockets) that these echoes cannot be explained by anything else (such as turbulence).

"Adsorbtion of CFC on Carboxen during sampling in the stratosphere," Susanne Roslin (Umeå University)

DESCARTES is a balloon-borne instrument for the measurement of long-lived trace
gases in the stratosphere. The principle behind the instrument is that by letting a
measured amount of volume pass through sample tubes containing the adsorbent
Carboxen, trace gases will be trapped inside the sample tube while the rest is passing
through. The instrument adsorb CFC-11, CFC-113, CCl4 and CH3CCl3 in measurable
quantities but is optimised for CFC-11.
The seminar will focus on the adsorption efficiency of the sample tubes. Preliminary
results of my study will be presented. Can quantitative adsorption of primary CFC-11
be secured during sampling with DESCARTES in the stratosphere?

[TOP]

"The observation of gravity waves in Noctilucent Clouds." Peter Dalin (IRF-K)

We have considered one case of observation of gravity wave in the NLC observed above Sweden. Visual observations supplement substantially to radar measurements (Esrange and Andenes) with the finding of small and medium-scale of gravity waves and may be very useful in the analysis of their dynamics even the NLC being observed from one point. In the examined case both optical and radar observations revealed a gravity wave with approximately the same characteristics propagating from south-east to north-west direction. This direction coincides with what was found by Vincent and Fritts (1987) for medium-period waves in summer season.

"The EISCAT meteor method: a review and recent results", Asta Pellinen-Wannberg (IRF-K)

The most important stages of development of the High Power Large Aperture (HPLA) radar method for meteor observations is presented from the European Incoherent Scatter (EISCAT) Facility point of view. The strength of EISCAT for this application is its high latitudinal location, dual frequency and tristatic observation possibilities. Meteoroid vector velocities can be derived from the tristatic observations. At EISCAT they average at about 65 km/s, which can be related to large cross sections for collisional ionization in hyperthermal collisions. Recent very high resolution observations simultaneously from three directions show processes occurring as some meteoroids pass through the radar beam. Finally, intensive shower meteor input during 2002 Leonids is related to ordinary ionospheric incoherent scatter observations.

"Cluster multi-point observations of ion outflow", Hans Nilsson (IRF-K)

A case study of oxygen ion energization and outflow is presented. The data
show oxygen ions being energized to energies of up to 40 keV, the upper
energy limit for the CLUSTER CIS ion spectrometer. The most important finding
is that the energization appear to be isotropic at high altitude, in contrast
to lower altitude energization which is typically transverse to the magnetic
field.

Furthermore the multi-spacecraft configuration is used to analyze the observed
structures in detail. It is discussed what we can expect to observe for
different situations, and this is compared with actual observations. In
particluar a mesoscale event of strong heating and associated outflow appears
to show a temporal decay which is similar for the two observing spacecrafts.
This indicate that both spacecrafts were situated in a coherent region where
all field-lines had a similar history, as could for example be expected in
the flux bundle expected from a flux transfer event.

"A Solar Active Region Quasi-Biennial Fluctuation", Csilla Szasz and Johan Kero (IRF-K)

A quasi-biennial fluctuation has been detected in the time-series of the sunspot umbra/penumbra area ratio (U/P) on the basis of the Debrecen Photoheliographic Data. The study is based on an intermittent period of nearly eight years; the material comprises more than 18.000 individual sunspots.

In the seminar we will present information about the temporal behaviour of the U/P ratio, period analysis and umbral area dependence. The physical background of the phenomenon is yet unclear but it seems to belong to the growing family of mid-term fluctuations.

"Ion velocity distributions at higher altitudes observed by CIS/Cluster: Formation of shell-like distribution as observed in cometary pick-up ions?" Sachiko Joko (IRF-K)

During the years of 1986 and 1987, after exploring comet Giacobini-Zinner and comet Halley, a lot of observations and theoretical studies by means of computer simulation on cometary newborn 'pick-up' ions and their behaviours have been reported. Cometary newborn ions picked up by the solar wind are known to form shell-like configuration in velocity phase space at ralatively far upstream of the nuclei of comets, in which particle density is small enough to be collisionless and so that linear theory of electro-magnetic instabilities is considered to be applicable. By means of observations by the CIS instrument onboard the Cluster satellite, at the dayside magnetosphere, supposed to be in the poleward cusp or the mantle region with above 8 Re (Earth radii) in altitude, shell-like configuration in velocity distribution of O+ ions has been found (We believe so at this moment). In this seminar, I'll just present how the shell-like velocity distribution looks like and how related electro-static and electromagnetic data seem to be as the first stage of this study.

"Unification Scheme for Classical and Quantum Mechanics at All Velocities", Jane Zheng-Johansson (IOFPR, Nyköping)

I first review the whereabouts, especially the unsolved problems in my opinion, in the issues of physics relevant to here, including the interpretation of Schrötdinger's wave function, the nature of inertial mass, space and time, the picture of elementary particles in qft and in string theory, and the unification schemes, etc.

I then introduce our recently achieved result, The Unification of Classical and Quantum Mechanics. Our approach is to firstly derive a realistic submicroscopic model for vacuum (of a Dirac kind) based on overall experimental observations, establish Newtonian equation of motion of it under external perturbation, and solve. The solution and predictions are presented in two parts. (I) The fundamental formation of martial particles: Our solution shows that, a basic particle, which may be e.g. an electron, is composed of a tiny free aether-pole (a bare charge) and the mechanical wave disturbancesidentifying with electromagnetic wavesgenerated by it in the medium. When in motion, of velocity v (here (v/c)-->0), as a result of a first kind source effect this particle wave exhibits all of wave and dynamic properties known for a de Broglie wave, and is here called a Newton- de Broglie (NdB) particle wave. In a confined space, the Newtonian solution for the NdB particle wave is equivalent to that given by Schrödinger's quantum mechanics. Through this general scheme for particle formation we have accomplished a basic task of the unification of classical- and the quantum- mechanics, both in terms of the deduction of the latter from the former, and the convergence of the latter into the former at high velocities. And we unfold the origins of a series of phenomena including the electromagnetic waves, the electromagnetic radiation and absorption, atomic and thermal excitations, the inertial mass, the Schrödinger's wavefunction and de Broglie wave, the Heisenberg's uncertainty relation, the de Broglie relations, the simultaneous existence of electron and positron or generally of particles and their anti-particles, the (rest) mass-energy equivalence relation, etc. (II) The Theory of Relative motion: (A) we show that the (v/c)^2-dependent terms yield in the particle wave and dynamic quantities a second kind source motion effect (SSME). The SSME augments the particle mass, and the wavevector and frequency of the particle's constituent waves, etc., by a factor \g = 1/\sqrt{1-v^2/c^2} in the v-direction; and conversely for the reciprocal quantities. Subsequently a moving body comprising the so affected particles will present a simultaneous length and time contractions (of Lorentz-Fitzgerald kind) as measured in the frame attached to the body. (B) A systematic survey of pivotal experimental indications leads us to conclude that the light velocities, c measured in vacuum and c' measured by a moving observer, and the observer's v obey the common triangle law of vector addition, conforming to the Galilean transformation (GT). (C) Combining (A) and (B) yields a set of transformation equations between an inertial reference frame at rest (in vacuum) and one moving relative to it, called Galilean-Lorentz transformation (GLT). The GLT together with the underlying theoretical basis of the general scheme yields a consistent Theory of Relative Motion. With the theory, we predict the observational null-/constant- fringe shift result of the Michelson-Morley/Kennedy-Thorndike experiment, the Doppler effects of electromagnetic waves, the equivalence principle of Newton's laws of motion in all inertial frames, etc, and we extend the classical and quantum mechanics to (v/c)^2 >>0. The complete agreement is in turn a justification of the general scheme.

Finally, I outline the on-going and planned research problems within our unification projects, these including the derivation of Schrödinger's equations from Newton mechanics, the formulations of a microscopic theory of gravity, and a theory of relative motion in non-inertial frames, and a treaty of cosmological problems.

"Simulated ENA images of the Venus-solar wind interaction region", Herbert Gunell (IRF-K)

We present simulated images of energetic neutral atoms (ENAs) produced in charge exchange collisions between solar wind protons and neutral atoms in the exosphere of Venus.

The ENA images are generated through the integration of the ENA production along lines of sight to a virtual ENA instrument. A model, that is based on measurements, of the neutral gas density in Venus' upper atmosphere is used in combination with a model of the plasma flow around Venus. The plasma model is a semi-analytical MHD model developed by Helfried Biernat and Nikolai Erkaev.

The images are found to be dominated by two local maxima. One produced by charge exchange collisions in the solar wind, upstream of the bow shock, and the other close to the dayside ionopause. The simulated ENA fluxes at Venus are lower than those obtained in similar simulations of ENA images at Mars.

"Quenching rates of O(1D) in the upper thermosphere", Tima Sergienko (IRF-K)

The 6300Å (red line) originated from the metastable O(1D) state is extensively used in the optical remote sensing of the upper atmosphere. The radiative lifetime of the 1D sate is rather long (~110 sec) and collision quenching by atmospheric gases is significant loss process for this state. Therefore the quenching rate coefficients are crucial in determining the 6300Å emission. While rate coefficients for quenching by N2 obtained in laboratory measurements and deduced from aeronomical observations are in good agreement, the importance of quenching by atomic oxygen is still under debate. Multipoint Auroral Large Imaging System (ALIS) measurements of enhanced 6300Å airglow caused by HF pumping in the ionosphere from the EISCAT-Heating facility were used to determine the effective lifetime of O(1D) state in altitude range of 200-300 km. The quenching rate coefficients obtained from the altitude dependence of the O(1D) lifetime are discussed.

Autumn Semester 2002

3 October

Carl-Fredrik Enell (IRF-K), Optical Studies of Stratospheric Clouds. [Abstract]

17 October

Narayana Rao (IRF-K), UTLS Ozone Variations over Northern Europe. [Abstract]

24 October

Johan Arvelius (IRF-K), The Problem of Identifying Tropopause Folds in Ozone Soundings Avoiding Seasonal Biases. [Abstract]

14 November

Peter Dalin (IRF-K), An Estimation of Inertio-Gravity Wave Parameters in Noctilucent Clouds. [Abstract]

21 November

Sachiko Joko (IRF-K), Ionospheric Ions Outflowing at High Altitudes in the Dayside Magnetosphere. [Abstract]

Tuesday 26 November

Rickard Lundin (IRF-K), Ponderomotive Forces in the Magnetosphere. [Abstract]

5 December

Herbert Gunell (IRF-K), Beam-Plasma Interaction. [Abstract]

12 December (10-10.30)

Professor Liu (Center for Space Science and Applied Research, China), A Brief Introduction to the Chinese Double Star Project.

12 December (10.30-11)

Dr Li (Center for Space Science and Applied Research, China), The Plasma Sheet Oscillation and Compressional Pc5 Pulsations in the Magnetotail.

12 December (11-11.30)

Pontus C:son Brandt (Applied Physics Laboratory, USA), Usefulness of ENA Imaging for Magnetospheric Research: New IMAGE Results.

19 December

Khaled Fadel (IRF-K)

Friday 20 December

Gösta Gahm (Dept of Astronomy, Stockholm University), The Architecture of Interstellar Clouds.


ABSTRACTS

Optical Studies of Stratospheric Clouds, Carl-Fredrik Enell (IRF-K)

This seminar is a short summary of the methods used and developed in my PhD thesis, "Optical studies of polar stratospheric clouds and related phenomena". The principles of zenith-sky scattering and the use of bistatic imaging will be discussed and a few of the results discussed. It is shown that PSC presence can be detected, but probably underestimated, with zenith-looking photometers. A case study of PSCs by bistatic imaging shows changes on very short temporal and spatial scales.

UTLS Ozone Variations over Northern Europe, Narayana Rao (IRF-K)

There has been growing interest in the upper troposphere and lower stratosphere (UTLS) region in the atmospheric scientific community over the past few years for various reasons. They include concerns about increase in emissions, in particular NOx, from subsonic and supersonic aircrafts, which normally fly in this region and variations of ozone trends with height as well as spatial variations. Different 3-D global chemistry and transport models have estimated a NOx perturbation of 20-70% in the 8-12 km layer, causing an increase in O3 concentration by 2-9% through photochemical reactions. Observed trends in ozone shows interesting features with large decreases in the lower stratosphere at high and mid latitudes in both hemispheres, while the trends in the troposphere shows regional differences with a positive trend over Europe, a negative trend over Canada and no statistically significant trend over North America. However, most of the results on trends and seasonal variation of ozone are based on the data collected at mid-latitudes and Canadian Arctic stations. There are no reported reliable long-term measurement series of ozone in the European Arctic mainly because of the paucity of the long-term measurements of ozone. Most of our understanding on European Arctic ozone is based on results from a series of large campaigns, for instance EASOE, SESAME, THESEO, SOLVE, conducted in the European Arctic augmented by some other small campaigns. So in this talk, I will discuss about variations of ozone (annual as well as interannual) over northern Europe using a relatively long-term database of 7 years. I would also like to discuss the relation between ozone and potential vorticity. Further, I will present preliminary results on the climatology of tropopause folds at high latitudes.

The Problem of Identifying Tropopause Folds in Ozone Soundings Avoiding Seasonal Biases, Johan Arvelius (IRF-K)

A discussion forum on the easily-explained problem of looking for tropopause folds in ozone soundings avoiding seasonal biases. Hopefully the discussion will concern the problem of looking for similar structures in data with variable structure.

An Estimation of Inertio-Gravity Wave Parameters in Noctilucent Clouds, Peter Dalin (IRF-K)

The case study of the Noctilucent Cloud (NLC) appearance on August 10-11, 2000 is examined. The clear wave dynamics are observed and the inertio-gravity wave is supposed to be responsible for the observed modulation in the NLC field. With the Esrange MST Radar data and Andøya MF Radar data we have managed to find the inertio-gravity waves which propagate upward from the stratosphere to the NLC altitude and could be responsible for observed wave dynamics in the NLC.

Ionospheric ions outflowing at high altitudes in the dayside magnetosphere, Sachiko Joko (IRF-K)

At the last spring EGS assembly I presented a case study of the ionospheric ions, especially O+ ions in this case, outflowing at high altitudes (higher than 6 Re) in the dayside magnetosphere observed by CIS/Cluster. I have continued to study this case and in this seminar I present several additional issues including other cases. The case of "12 April, 2001" shows that O+ ions were continously accelerated/energized during the whole orbit from the duskside polar cap, the cusp and the magnetopause to the magnetosheath. But the acceleration/energization processes differed depending on the altitude. As for ion species differencies, O+ and H+ behaved in different ways, by which I mean that the influence of the acceleration/energization processes on each ion species seem to be different. In this seminar, if we have enough time left, Hans Nilsson will give a short talk on issues relevant to mine, based on his presentation at the last COSPAR congress.

Ponderomotive Forces in the Magnetosphere, Rickard Lundin (IRF-K)

We review the current state of the art in the study of ponderomotive forces caused by ULF electromagnetic waves in the terrestrial magnetosphere. This field of research has attracted considerable attention in recent years. Even though the literature on the subject is quite extensive, there are still challenging questions encountered in applying the concept of ponderomotive forces to analysis of concrete space phenomena. The review presents a brief but clear and rational account of the subject from the basics up to problems of interest to research workers in the field of space physics. The hydrodynamic, quasi-hydrodynamic and test-particle approaches are used for description of ponderomotive acceleration and redistribution of ions in the ionosphere-magnetosphere coupled system. Theoretical problems of the ponderomotive wave-particle interaction are discussed in the light of recent satellite investigations of the auroral acceleration processes. We conclude that the ponderomotive forces play an important role in the structures and dynamics of the magnetosphere.

Beam-Plasma Interaction, Herbert Gunell (IRF-K)

This seminar concerns the interaction between an electron beam and a
plasma. Laboratory experiments were conducted using two different
setups; one with an electric double layer and the other with a hot
cathode as the electron beam source.
In both experiments the it was found that the electrostatic waves
generated by the beam-plasma interaction can concentrate to a narrow
spike with a full width at half maximum that is on the order of one
wavelength.
The narrow electric field spike has been reproduced in a one-dimensional
electrostatic particle in cell simulation. The spike is formed
only when the interaction occurs in the plasma density gradient that
surrounds a double layer and exists in front of a hot cathode. The
electron beam is spread in velocity space as it passes the spike.
Based on a simplified fluid descriptions of eigenmodes of a plasma
diode with a density gradient the localisation of the spike, spatially
and in frequency, can be explained. The conclusion, that is proposed
here, is that the spike can be seen as a coupled system of two such
eigenmodes that receive their energy from the beam-plasma interaction.

Spring Semester 2002

4 February

"Kan man höra norrskenet? Den naturvetenskapliga bakgrunden till ljudfenomen i samband med starka norrsken". Seminar by Christer Jurén, IRF Kiruna.

14 March

"Observations and Analysis of Artificial Aurora". Seminar by Björn Gustavsson, National Institute of Polar Research, Tokyo, Japan.

21 March

"Case Studies of the Dynamical Development of Polar Stratospheric Clouds Using Multistatic Imaging". Seminar by Carl-Fredrik Enell, IRF Kiruna. [Abstract]

28 March

"Locations of proton isotropic boundaries as measured by conjugate high-altitude and low-altitude satellites". Seminar by Natalie Ganushkina, FMI. [Abstract]

9 April

"Substorm results from Interball" and a report from the substorm conference in Seattle by Ingrid Sandahl, IRF Kiruna.

11 April

"Cluster high-altitude observations of ionospheric plasma outflow". Seminar by Sachiko Joko, IRF Kiruna [Abstract]

18 April

"Response of Polar Mesosphere Summer Echoes to Ionospheric Heating". Seminar by Evgenia Belova, IRF Kiruna. [Abstract]

2 May

"Trends in Moscow NLCs occurrence and brightness." Seminar by Petr Dalin, IRF Kiruna. [Abstract]

16 May

"Aerosols, clouds and climate." Seminar by Johan Arvelius, IRF Kiruna. [Abstract]

21 May

"Longtime DOAS observation of trace gases in Kiruna." Seminar by Thomas Wagner, Heidelberg, Germany.

30 May

"Auroral radiation of Jupiter." Seminar by Anil Bhardwaj, Space Physics Laboratory, Vikram Sarabhai Space Centre, India.

31 May

"Space Program of India." Seminar by Anil Bhardwaj, Space Physics Laboratory, Vikram Sarabhai Space Centre, India.

4 June

"Fast volume rendering." Seminar by Mats Holmström, IRF Kiruna. [Abstract] NB: in the Aula.

7 June, 1.30 p.m.

"Waves and Fluctuations in Non-Maxwellian Plasmas." Seminar by Herbert Gunell, Dept. of Physics and Astronomy, University of Iowa. [Abstract] NB: in the Aula.


ABSTRACTS

"Case Studies of the Dynamical Development of Polar Stratospheric Clouds Using Multistatic Imaging". Seminar by Carl-Fredrik Enell, IRF Kiruna.

The important role of polar stratospheric clouds (PSCs) in
stratospheric chemistry is firmly established. The formation of PSCs
is closely related to temperature, which is affected by wave activity
on different scales. PSC occurrence thus reflects radiative and/or
dynamical stratospheric temperature changes.
The most obvious indication of PSC presence is the visual observation
of mother-of-pearl clouds. We present case studies of the development
of visual PSCs undertaken by means of ground-based cameras. Our
observations show that the presence of mother-of-pearl clouds varies
on a scale smaller than that of typical mesoscale models.
The images are studied further in the context of the meteorological,
dynamical situation, and visibility conditions (solar elevation and
tropospheric cloudiness).

"Locations of proton isotropic boundaries as measured by conjugate high-altitude and low-altitude satellites". Seminar by Natalie Ganushkina, FMI.

Polar CAMMICE MICS data of proton pitch angle distributions with energies
of 31-80 keV for the period of 1997-1998 were analyzed to determine the locations where
anisotropic pitch angle distributions (perpendicular flux dominating) change to isotropic
distributions. We study this high-altitude isotropic distribution boundary
(IDB) in terms of its location in L-shell and MLT. Statistical results
showed that this boundary is located at lower L-shells on the nightside and
at higher L-shells on the dayside with most distant location at dawn. With
the increase of magnetic activity, the IDB positions shift towards lower
L-shells at all MLT. The locations of IDBs were also determined for
different storm phases. A superposed epoch analysis revealed that the
L-shells of the IDBs move to lower L-shells with decreasing Dst and to
higher L-shells during Dst recovery. Several events were selected during
which simultaneous observations in the same local time sector were
available from Polar at high altitudes and from DMSP at low altitudes. The
magnetic field mappings to find the relative locations of both spacecraft
were made using the Tsyganenko T01 model with the observed solar wind input
parameters. The mappings showed that Polar and DMSP were placed on nearly
the same field lines, which leads us to suggest that the Polar IDB and the
b2i boundary at DMSP are closely related, and that the mapping between high
and low altitudes can be made sufficiently accurately.

"Cluster high-altitude observations of ionospheric plasma outflow". Seminar by Sachiko Joko, IRF Kiruna.

With respect to ionospheric-origin O+ ions upflowing through the polar cap, cusp/cleft or mantle, and magneto-
sheath, observed by Cluster/CIS above 3-Re altitude, increase of parallel flow velocity seems to be fed
by increase of transverse energy, as shown also by the previous study of Lundin and Hultqvist (1989), but on the other hand, parallel flow velocity continues to increase by some other processes, like pressure gradient or inertial drift.

"Response of Polar Mesosphere Summer Echoes to Ionospheric Heating". Seminar by Evgenia Belova, IRF Kiruna.

Polar mesosphere summer echoes (PMSE) are abnormally strong radar returns
that occur during summer months near the mesopause at high latitudes. They
were discovered about 20 years ago. It seems that PMSE reflect complicated
processes occurring in a multi-component plasma consisting of electrons,
ions and charged aerosols, and so far there is no clear understanding of
the mechanism of PMSE. In order to influence the electron component during
PMSE events, we conducted, in summer 1999, a joint PMSE/Heating experiment
using the EISCAT VHF radar and the EISCAT Heating facility. During our
experiment we demonstrated that PMSE was indeed affected by the heating
pulses, with the back-scattered signal decreasing when the heater was on.
The response time was less than 2 seconds. (Chilson et al., 2000). We have
now analysed the backscattered powers for selected time intervals and
heights for different PMSE/heating experiments with the highest available
time resolution of 29.85 ms. We find that there is an upper limit for the
time which it takes for PMSE power to respond to switching the heater on or
off which is less than 30 ms. Such a rapid response of the PMSE allows us
to differentiate between mechanisms which could be responsible for the
heating effect on PMSE. We find that enhancment of electron diffusivity
during heating is unlikely to be able to account for so rapid a decrease of
radar backscattered power when the heater switches on. We suggest that
increase of the Debye length up to half a radar wavelength due to electron
heating in a presence of aerosols might explain the heating effect on PMSE.
The time constant for this process is expected to be in the 1 ms range.
Finally, we make a proposal for the next PMSE/heating experiment which is
planed to conduct in summer 2002.

"Trends in Moscow NLCs occurrence and brightness." Seminar by Petr Dalin, IRF Kiruna.

NLCs near Moscow, Russia are observing in specially organized campaigns
every summer season from 1962 up to present time. During this period all
the observers have been following the same procedure of NLC registration
and accompanying comments, elaborated in 1962.
Some statistical results were obtained from the database. One of its
important advantages is an accurate accompanying meteorological information. It allowed to
separate the cases of NLC no-registration due to a break in observation or
due to a bad weather from the cases of real absence during a clear night.
Such separation proved to be substantial for obtaining of geophysical
significant statistical results for NLC parameters. Long-term behaviour of
seasonally averaged NLC parameters was studied. Most interesting results of
this investigation are decadal (about 10 years) variability, zero trend in
a NLC occurrence probability for a clear night and a positive trend in
seasonally accumulated NLCs brightness (normalized by the number of clear
nights). The difference between this result and well-known result of
M.Gadsden (1990) is discussed.

"Aerosols, clouds and climate." Seminar by Johan Arvelius, IRF Kiruna.

I will present some of the contents from the course "Aerosols, clouds and climate" that I
participated in this winter. The contents was (luckily) not as broad as the
title indicated. It was rather about the climatic effects of antropogenic
aerosols both directly and indirectly from their impact on the cloud
formation processes. This large perspecive will be discussed as well as
the modifications to the Köhler theory of partly soluable aerosols and
gases as well as surfactants.

"Fast volume rendering." Seminar by Mats Holmström, IRF Kiruna.

It is difficult to interpret observed energetic neutral atom (ENA)
images, since an image only depends indirectly on the quantities that
usually are of interest - the distribution of ions and neutrals.
For a detailed, quantitative, analysis of observed images one can use
inversion techniques to extract parameters from a mathematical model
of the ENA production. Basically, we generate images until we find
one that closely match the observed image. The parameters that
produce the best match is our parameter estimate. The sequence of
generated images is determined by the chosen minimization algorithm.
Thus, to solve the inverse problem, hundreds, or even thousands, of
images must be generated and it is crucial that we can generate each
image as fast as possible.
Computer imaging of volume emissions is a general problem, of which
ENA imaging is just a special case. In computer graphics this process
is denoted volume rendering. We have developed an hierarchical,
wavelet based, method for fast imaging of volume emissions. The
proposed method also provides error estimates and error control,
automatically. The approach is to find a sparse representation of the
volume emission, a three-dimensional function, before the projection
onto the image plane. The representation is based on conservative
subdivision. Numerical experiments suggest that the proposed method
can be orders of magnitude faster than traditional line of sight
integration, for similar errors in the generated images.

"Waves and Fluctuations in Non-Maxwellian Plasmas." Seminar by Herbert Gunell, Dept. of Physics and Astronomy, University of Iowa.

A simple pole expansion can be used to model the distribution function for
the purpose of calculating dispersion relations for electron waves
(Lfgren and Gunell, Phys. Plasmas, vol. 4, pp.3469-3476, 1997) and
ion-acoustic-like waves (Gunell and Skiff, Phys. Plasmas vol. 8, pp. 3550-3557, 2001). The
expansion is a rational function of the complex phase velocity, and the
integration along the real axis is reduced to a sum of the residues at the
poles of the expansion of the distribution function.
For waves on the ion acoustic time scale we find that slow weakly damped
modes exist in two-temperature plasmas, and in plasmas with beam-like
tails, i.e. plasmas where the ion distribution consists of two components
centred at different velocity. These slow, weakly damped, acoustic-like
modes exist also when the tail component constitutes a small fraction of
the total ion density. These weakly damped modes have been observed in
laboratory experiments (Skiff, De Souza-Machado, Noonan, Case, and Good,
Phys. Rev. Letters, vol. 81, p. 5829, 1998). For plasmas with equal ion
and electron temperatures weakly damped modes are found when there is a
depletion of the high energy tails. Weakly damped modes are also found in
plasmas with equal ion and electron temperatures in the presence of a low
density cold ion component.
Electrostatic fluctuations appear in stable plasmas due to the
discreteness of the plasma particles. The calculation of the spectral
density of these fluctuations in an isotropic three-dimensional plasma
through superposition of the electric fields of dressed test particles is
described in textbooks (e. g. Krall and Trivelpiece, Principles of Plasma
Physics. New York: McGraw-Hill, 1973). The test particle method has been
used to calculate the spectral density for electrostatic fluctuations in a
plasma where the particles follow a kappa distribution (Mace, Hellberg,
and Treumann, J. Plasma Physics, vol. 59, pp.393-416, 1998).
Here we show how the electrostatic fluctuations can be calculated for in
plasmas where both the ion and electron distributions are described by
simple pole expansions, in 1D and isotropic 3D plasmas. We present
calculations of the spectral density of the fluctuations as a function of
frequency and wavenumber. For comparison with measurements we integrate
over wave number to obtain the spectral density as a function of
frequency only.


Autumn Semester 2001

23 August

Evidence for impulsive solar wind plasma penetration through the dayside magnetopause, Rickard Lundin, IRF [Abstract]

30 August

Recent Cluster CIS (Cluster Ion Spectrometry) results, Rickard Lundin, IRF

11 September

Comment on V.M.Vasyliunas, "Electric field and plasma flow: What drives what". Seminar by M. Yamauchi, IRF [Abstract]

23 October

The Use of Stratosperic Tracer-Interrelationships to study chemical reactions in the Spring Polar Vortex. Seminar by Johan Arvelius, IRF [Abstract]

30 October

First results from RAPID on Cluster. Seminar by Ingrid Sandahl, IRF [Abstract]

1 November

Analysis Technique School for Space Plasma Data. Seminar by Sachiko Joko [Abstract]

6 November

Fast neutral atom imaging: A journey to Mars, Mercury, and back. Seminar by Mats Holmström [Abstract]

15 November

The Munin Plasma Data. Seminar by Kan Ogawa [Abstract]

20 November

Framtiden för IRF:s jonosonderingar med anledning av ett nytt anslag på 890 tkr från Kempestiftelserna. Seminar by Christer Jurén [Abstract] NB: Seminar to be held in the Auditorium (Aulan)

27 November

Fine structure of the diffuse auroral zone observed simultaneously by ALIS and the FAST satellite. Seminar by Tima Sergienko.

29 November

Cosmic Dust Measurements with HPLA radars. Seminar by Asta Pellinen-Wannberg.

4 December

Are there clouds in the winter mesosphere? Seminar by Sheila Kirkwood. [Abstract]

11 December

En kamera är väl en kamera? Ett seminarium om äpplen och päron. Seminar by Urban Brändström [Abstract]

ABSTRACTS

Evidence for impulsive solar wind plasma penetration through the dayside magnetopause, Rickard Lundin, IRF Kiruna.

This seminar will present in-situ observational evidence from the Cluster Ion Spectrometer, CIS, on Cluster of injected solar wind "plasma clouds" protruding the dayside high-latitude magnetopause. The plasma clouds, presumably injected by a transient process through the dayside magnetopause, show characteristics implying a generation mechanism denoted impulsive penetration (Lemaire and Roth, 1977). The injected plasma clouds, here termed "plasma transfer events", PTEs (Woch and Lundin, 1991), are temporal in nature and relatively limited in size. They are initially moving inward with a high velocity, and a magnetic signature that makes them essentially indistinguishable from regular magnetosheath encounters. However, well inside the magnetosphere PTEs are more easily distinguished from magnetopause encounters. The PTEs may still be moving while embedded in an isotropic background of energetic trapped particles. Well inside the magnetosphere they expand along magnetic field lines. However they frequently also have a significant transverse drift component. The drift is localised, thus constituting an excess momentum/motional emf generating electric fields and currents. The induced emf also acts locally, accelerating a pre-existing cold plasma (e.g. Sauvaud et al, 2001). Observations of PTEs-signatures range from "active" (strong transverse flow, magnetic turbulence, electric current, local plasma acceleration) to "evanescent" (weak flow, weak current signature).

Comment on "Electric field and plasma flow: What drives what" by V.M. Vasyliunas, GRL, Vol 28, No, 11, June 2001. Seminar by M. Yamauchi, IRF Kiruna.

Vasyluinas recently revisited the cause-effect problem of ExB drift and
polarization (VxB) electric field in magnetohydrodynamics (MHD)
[Vasyluinas, 2001]. He substantially proposed two critical things: (1)
inclusion of displacement current instead of conduction current in Ampere's
law; (2) Viewing cause-effect relation as the initial value problem. With
straight forward mathematical formulation under given assumptions, initial
condition, Ohm's law, and boundary condition, he showed that in 3-D free
space a given convection with finite linear initial momentum causes
electric field which altogether keep the momentum whereas a given
distribution of electric charge does not generate substantial linear
momentum but only a mere oscillation. This is a beautiful formulation of
plasma oscillation in MHD regime.
However, his lacks two important things:
(1) He did not include source terms (or boundary condition) in his
formulation and he ignored non-uniform condiiton. As a result the
formulation is not applicable to the large-scale space phenomena although
the formulation is correct.
(2) He completely forgot the original causality of MHD equations. While
mass conservation law is not cause-effect relation, the momentum equation
and the induction equations are causality equations which we need special
care. Then we have "time scale of frizen-in condition" concept, which is
important for Solar wind plasma enter to the magnetosphere without pilling
up the magnetic field.
The Use of Stratosperic Tracer-Interrelationships to study chemical reactions in the Spring Polar Vortex. Seminar by Johan Arvelius, IRF Kiruna
A refresher of the idea of Stratospheric Tracers and their
interrelationships that I've given a couple of seminars on earlier.
Thereafter there will be a presentation of some resent studies that use
these to quantify chlorine and bromine activation and the following ozone
depletion in the northern polar stratosphere during the SOLVE/THESEO 2000
campaign winter 1999/2000.

First results from RAPID on Cluster. Seminar by Ingrid Sandahl, IRF Kiruna

RAPID, the high energy particle instrument on Cluster, measures electrons
in the energy range 20-400 keV and ions from 30 to 1500 keV. There is also
an ENA mode. There have been a number of initial operation problems and
some sensor heads have suffered degradation of sensitivity, but the RAPID
instruments on all spacecraft are now giving scientifically useful data. In
this seminar the RAPID instrument will be described and initial results
will be presented. I will also discuss the capabilities as well as problems
of the instrument.

A report on the meeting in La Londe les Maures in October on Analysis Methods for Multi-Spacecraft Data. Seminar by Sachiko Joko, IRF Kiruna

Sachiko will talk about:
Analysis Technique School for Space Plasma Data
- not on contents in detail but useful information for you
This school (course) aims to get and exchange advanced analysis
skills, including basic concepts, on space plasma data analyses.
This sounds limited to space plasma, but it's not true, I think.
Actually this course, in some senses, gave me hints for analysis
techniques. I'd like to say that these techniques are just applied
to space plasma data analyses!
Anyhow, this course roughly consisted of:
1. Statistics
2. Spectral Analysis
3. Multivariate Analysis
4. Nonlinear Time Series Analysis
5. Neural Nets (Artificial Intelligence)
6. Others
I'll try to present what I've become acquainted with going through this
course. So this presentation will not be a technical one.

Fast neutral atom imaging: A journey to Mars, Mercury, and back. Seminar by Mats Holmström, IRF Kiruna

In this talk, Mats Holmström will present simulation results for,
and discuss:
* ENA albedo images, and directional fluxes, near Mars,
* the imaging of sputtered very low energy neutral atoms (VLENA),
* the distribution of neutrals and ions near Mercury,
* a characteristic method for computing phase space density, and
* an algorithm for fast volume rendering.

The Munin Plasma Data. Seminar by Kan Ogawa (Japan)

In this seminar, Kan Ogawa will talk about the plasma data observed by the Munin
satellite. The Munin satellite was launched on November 21, 2000 and it
collected data for nearly 3 months. Also, he will present the observed ion
injection events.

Framtiden för IRF:s jonosonderingar med anledning av ett nytt anslag på 890 tkr från Kempestiftelserna. Seminar by Christer Jurén, IRF Kiruna

* Matematisk beskrivning av "tillväxt" vid IRF.
* Ansökan om en Miljon.
* Den historiska utvecklingen av jonosonderingen vid IRF, FOA, Chalmers...och i hela världen.
* Jonosfären.

Are there clouds in the winter mesosphere? Seminar by Sheila Kirkwood, IRF Kiruna

It is well known that clouds sometimes appear in the winter stratosphere
(polar stratospheric clouds) and the summer mesosphere (noctilucent
clouds). But it is generally believed that the atmosphere above the
tropopause is otherwise free of clouds.
During the last year, the ESRAD MST radar has observed thin layers of
enhanced radar echoes in the winter mesosphere (50-80 km altitudes) during
almost all of the solar proton events which have ocurred. These layers are
extremely thin, highly aspect sensitive and are seen only when the
mesosphere is illuminated by sunlight. Arguments will be presented that
they are caused by thin layers of aerosols, i.e. clouds?

En kamera är väl en kamera? Ett seminarium om äpplen och päron. Seminar by Urban Brändström, IRF Kiruna

Idag kan många olika sorters kameror avbilda norrsken. Vad är skillnaden mellan en vanlig småbildskamera, vår firmamentkamera från 1977, ALIS-kamerorna från 1994 och den nya firmamentkameran från år 2000? Hur förhåller sig dessa instrument till liknande instrument i våra grannländer? Är det skillnad mellan rymd och markbaserade kameror? Varför går norrskensfilmerna alltid för fort?
IRF har tidigare haft ett mycket aktivt och innovativt forskningsprogram för optisk norrskensforskning. En sammanfattning av de senaste tio årens verksamhet kommer att ges.
En populärvetenskaplig film om optiska mätningar, ca. 8 min speltid, kommer att visas under seminariets gång. (Samma film som visades under Öppet hus).
Det kommer att vara gott om tid för diskussioner och frågor.

Spring Semester 2001

11 January 2001

"Modelling small-scale mountain lee-waves over Kiruna", by Sheila Kirkwood, IRF, Kiruna [Abstract]

16 January 2001

"The Munin Project", by Olle Norberg, IRF, Kiruna

13 February 2001

"Simulations of Charge-Exchange Processes near Mars", by Mats Holmström, IRF, Kiruna [Abstract]

15 February 2001

"The Physics of the Cusp from an Interball Perspective", by Ingrid Sandahl, IRF, Kiruna [Abstract]

22 February 2001

"Numerical simulations of the One-Dimensional Vlasov Equation" by Bengt Eliasson, Departments of Scientific Computing and Astronomy and Space Physics, Uppsala [Abstract]

Friday, 23 February 2001 (10.30-11.30)

"The Solar Wind and Geomagnetic Storms" by Prof. Y. Kamide, STE LAB, University of Nagoya, Japan

1 March 2001

"Interplanetary Dust Studies using Large Aperture Radars meteor observations" by Diego Janches, IRF, Kiruna

6 March 2001

Professor A. Suzuki, Saga University, Japan. A seminar presenting his university, its education/research system and his work on Magsat satellite data.

15 March 2001

"Energized heavy ions measured by Interball -2 satellite" by Sachiko Joko, IRF, Kiruna [Abstract]

16 March 2001

"Lower Hybrid Cavities and Other Plasma Phenomena in the Subauroral Region" by Solveig Høymork, IRF, Kiruna [Abstract]

22 March 2001, 10:00 (10 am)

"Fine Structures in Auroral Emissions" by Jim LaBelle, Dartmouth College [Abstract]

22 March 2000, 13:30 (1.30 pm)

"Wave Propagation in Inhomogeneous Plasmas" by Hans Pécseli, University of Oslo, Norway [Abstract]

5 April 2001

Reports from EGS XXVI General Assembly in Nice, France, 25-30 March 2001

10 April 2001

"Direct Magnetosheath Plasma Injections into the Closed Geomagnetic Field Region Observed at Mid- and Low-altitudes" by Yamauchi Masatoshi, IRF, Kiruna [Abstract]

26 April 2001

"Motion and Origin of the Noon Poleward Moving Auroral Arcs" by Alexander Kozlovsky, Oulu University, Finland [Abstract]

8 May 2001

"Imaging of PSCs in 0-3 dimensions" by Carl-Fredrik Enell, IRF, Kiruna [Abstract]

10 May 2001

"Inertial Resistivity and Current Limitation in a Collision-free and Inhomogeneous Plasma" by Martin Bohm, Department of Space Physics, Umeå University, Kiruna [Abstract]

15 May 2001

"The Frontal Systems, Fundamentals", by Narayana Rao, IRF, Kiruna


ABSTRACTS

"Numerical simulations of the One-Dimensional Vlasov Equation", by Bengt Eliasson, Department of Scientific Computing and Department of Astronomy and Space Physics, Uppsala

In order to facilitate numerical simulations of plasma
phenomena where kinetic processes are important, we have
studied the technique of Fourier transforming the Vlasov equation
analytically in the velocity space, and solving the resulting
equation numerically. Special attention has been paid to the
boundary conditions of the Fourier transformed system, avoiding
the so-called recurrence phenomenon.
I will make a short presentation of the numerical techniques
and then present some numerical results; the process of
electrons getting trapped in waves (nonlinear Landau damping),
comparison with thery of linear waves etc.
We are currently looking on a problem of tunneling of information
throught the ionosphere, where the tunneling may be caused by
electrons trapped in the self-consistent electrostatic potential
due to the ion density profile. I will show some
numerical results from this problem.

"The physics of the cusp from an Interball perspective", by Ingrid Sandahl, IRF

The Interball project has given important contributions to our
understanding of the morphology and the physical processes in the cusp and
cleft. Interball-Tail and Magion-4 have performed more extensive
measurements in the high altitude cusp than any previous spacecraft.
Interball has also been a part in the ISTP program and data have been used
in many multipoint studies. In this paper cusp studies based entirely or
partly on Interball data will be reviewed.
The high altitude cusp/cleft is always a clearly distinguishable feature.
It is wider than suggested by direct mapping from low altitude, but the
position is controlled by the solar wind in a similar way as the low
altitude cusp. The dependence of the high altitude cusp position on IMF By
is, however, smaller than expected. Above the cusp/cleft there is almost
always a region of strong ULF turbulence and low magnetic field, the
turbulent boundary layer, TBL. The TBL extends tailward from the cusps and
is proposed to be related to the magnetospheric "sash".
The cusp is the site of very many physical processes. It acts like a funnel
collecting magnetosheath plasma into the magnetosphere. A number of
different plasma entry mechanisms are supported by the data including
direct plasma entry through the turbulent boundary layer, direct entry
along open high-latitude field lines, sub-solar point reconnection, and
lobe reconnection. For the overall magnetosheath plasma entry into the
magnetosphere, however, the magnetotail boundary is probably more important than the cusp.
Cusp energetic particles (Å 100 keV-MeV) are observed by Interball, but
their origin is not well understood. One view is that they have drifted to
the cusp from the ring current and outer radiation belt.
Acceleration and outflow of ionospheric plasma also take place in the cusp.

"Simulations of Charge-Exchange Processes near Mars", by Mats Holmström, IRF-Kiruna

Ions interact with neutrals by charge-exchange.
We study the interaction between the solar wind
and Mars' exosphere.
The results of, and methods used in, the
simulations of two different problems are presented.
The production of energetic neutral atoms (ENAs)
and the production of X-rays, near Mars.
The production rate computations are based on an
empirical proton flow model and an exospheric model.
Using these parametric models, X-ray and ENA images
are generated by line-of-sight integration
(the forward problem).
The possibility of detecting the X-ray emissions
from Mars and Venus using the X-ray observatories
Chandra and XMM-Newton is discussed.
To speed up the computations and control the error,
a new algorithm for evaluation of line-of-sight
integrals is presented.
We also discuss the inverse problem of
extracting flow parameters from measured
ENA and X-ray images.

"Modelling small-scale mountain lee-waves over Kiruna", by Sheila Kirkwood, IRF.

Nacreous clouds, the brightly coloured type of polar straospheric clouds
which are often seen in the Kiruna area in January, often show clear
wave structure. The wavelength of the wave structures are of the order 30 km
or less. Model simulations of mountain lee waves in the stratosphere using
the MM5 meteorological model have been made for recent ozone research
campaigns by German and British groups. However, the lee-waves in these
simulations have have wavelengths of 100 km or more. There is clearly a
need to model the smaller-scale waves to aid in interpretation of
photographic records of the clouds, and ESRAD radar observations of the
vertical winds associated with lee-waves.
In this seminar a relatively simple model for small scale waves will be
presented. The model uses a 1-km resolution digital terrain model over
northern Scandinavia, synoptic atmospheric wind and buoyancy data from
UKMO assimilations and wave refrective index and ray-tracing concepts as
described by Salby.
The audience are invited to discuss how this model could be used in our
research and how it might usefully be improved.

"Energized heavy ions measured by Interball-2 satellite", by Sachiko Joko, IRF.

*Joko, S., IRF-K, Sweden, sachiko.joko@irf.se
Sandahl, I., IRF-K, Sweden, ingrid.sandahl@irf.se
Yamauchi, M., IRF-K, Sweden, masatoshi.yamauchi@irf.se
Sergienko, T., IRF-K, Sweden, timothy.sergienko@irf.se

Upward moving heavy ions with energies of up to at least 600 eV are
studied using the PROMICS-3 instrument on board the Interball-2
(Aurora Probe) satellite. While many past studies revealed O+ outflow
from the ionosphere, non-thermal escaping heavy ions, like N2+, NO+
and O2+, have not been well investigated, partly because of a lack of
proper instrumentation in previous mid- and high-altitude satellites.
PROMICS-3 on board Interball-2 is capable of measuring non-thermal
heavy ions because the instrument shares a mass spectrometer mode
(1-64 amu/q for 100 eV and 600 eV positive ions) and an energy
spectrometer mode (4 eV-70 keV ions for four masses and 0.3-35 keV
electrons).
We have examined all the Interball-2 observations (October 1996 -
December 1999) of heavy ions (m/q > 16) during geomagnetically
active periods (Kp >= 4). Heavy ions are observed in all MLT, i.e., in the noon
(cusp), dawn, dusk and midnight. According to the comparison between mass spectra
of upward moving heavy ions and the energy spectra of H+, O+,He+ and
He++ in the transverse direction, heavy ions events seem to be
associated with energized and upflowing O+ events.
These appear to be caused by large potential drops, seen as the ion
beam energy and related to plasma injection from the solar wind or the
plasma sheet.
Note:
1. "Energized Heavy Ions" should be changed like this;
"Molecular Ions". Compared to other studies on
this subject, 600eV that I'm now focusing on as a
fixed energy is much higher than others, but I prefer
just saying "molecular ions" or "heavy ions" (this
means 'heavier than lighter ions like O+ and N+').
2. I'd like to clarify the physical mechanism of "molecular
ions upflowing (escaping from the Earth)" as the goal
of this study, but I'm still under stastical study, which
means that I also encourage audiences to give me any ideas on this.

"Lower Hybrid Cavities and Other Plasma Phenomena in the Subauroral Region", by Solveig Høymork, IRF.

Solveig Høymork will present the main points in her thesis which analyses data from two Swedish satellites, Freja and Astrid-2. These satellites orbited the earth over the poles and took measurements in the auroral zone at heights of 1700 km and 1000 km respectively. This is the upper ionosphere where a large proportion of the atoms are ionized, creating a plasma. The study is restricted to the subauroral region. This area is expected to be less dynamic than the area in which aurora is usually visible. Nevertheless exciting phenomena occur there as well. Data shows localized thinning in plasma density, known as cavities. Both small-scale (ca 50 m) and large-scale (ca 1000 km) cavities have been observed. There are many physical processes that can lower the local density of plasma and thus create cavities, for example wave-particle interaction, electric fields and plasma transport. The thesis deals with several different types of cavities and localized higher density ion clouds, and gives possible explanations as to why these occur.
Both Freja and Astrid-2 were relatively cheap satellites. They have supplied a wealth of very interesting data and contributed to an increased understanding of our universe and some of the processes which affect its environment. It is becoming increasingly important to understand the environment in space , as more and more human activity takes place there (for example commercial satellites and space travel).

"Fine Structures in Auroral Emissions", by Jim LaBelle, Dartmouth College.

The aurora emits a variety of types of radio waves,
and most of these exhibit frequency fine structure;
i.e., they are composed of multiple discrete features
which often vary in frequency. This talk addresses the
fine structure in two of these emissions: auroral roar
and auroral Lanmuir waves. After reviewing the experimental
evidence for the fine structure of these emissions,
revealed in both ground-based and rocket-borne wave
receiver data, we explore the possibility that these
fine structures are consequences of the inhomogeneity
inherent in the auroral plasma. We put forth that both types
of fine structure may be explained by considering wave
excitation in the presence of density structures that
impose an eigenmode structure on the waves.

"Wave Propagation in Inhomogeneous Plasmas", by Hans Pécseli, University of Oslo, Norway

Models for describing the properties of waves propagating in inhomogeneous
plasmas are reviewed. Particular attention is given to electron plasma
waves (Langmuir waves) in plasmas containing density gradients, Alfvén
waves in inhomogeneous plasmas and ion sound waves in magnetized plasmas with inhomogeneous electron temperatures. It is shown how it can be argued that these waves are not following any dispersion relation for inhomogeneous conditions, and the concept is then "de-mystified".

"Direct Magnetosheath Plasma Injections into the Closed Geomagnetic Field Region Observed at Mid- and Low-altitudes", by M. Yamauchi

Some decade ago observations of Viking showed that direct solar wind
injection may occur deep inside the CPS region. Since then other
observations of plasma injection into CPS have been reported, from highly
transient injections to more stagnant ones with different magnetic
(field-aligned current) signatures. Such observations raises a question
identifying/defining the open-closed boundary.
Satellite cusp observations in 1990's also indicate that we do not have a
simple open-or-closed concept. It seems necessary to introduce a fuzzy
concept for the openness of regions such as "semi-open" and "extra-open"
(extra here means accessibility of ionospheric ions to the magnetosheath).
We also report on recent searches for direct plasma transfer with other
satellites. Interball-tail, from similar altitudes, found similar types of
events. Freja, from low-altitude, sometimes observes cusp-like injections
into early dawn and late dusk. Finally, data from Astrid-2 display
characteristics of ion clouds which could be attributed to direct
injections of the solar wind.

"Motion and Origin of the Noon Poleward Moving Auroral Arcs", by Alexander Kozlovsky, Oulu University, Finland

Near-noon auroral arcs were investigated together with the
ionospheric plasma flows derived from the EISCAT VHF measurements over

Svalbard. The auroral arc motion was monitored at 0800 - 1300 MLT by the

all-sky camera during four days in December 1998. It has been found that the
noon auroral arcs move poleward at the velocity of the order of 200 - 600
m/s, and this velocity does not show any dependence on the velocity of the
ionospheric plasma convection along the same direction. The arcs appear at 5
- 15 min after strong changes (up to 4 km/s) in the meridional plasma flow,
which resulted from variations in the interplanetary magnetic field.
Particle precipitation data from DMSP satellites show location of the
auroras on closed magnetic field lines in a vicinity of the boundary between
BPS and LLBL. Spectrums of the northward electric field variations measured
by the radar demonstrate clear peaks corresponding to the FLR oscillations.
Period of the oscillations increases from 6 min at 74.3 MLAT to 14 min at
76.4 MLAT. Corresponding spectral characteristics were observed in the
magnetic field measured on ground. The observed features allow to suggest
that the noon auroral arcs arise as a result of interference between Alfvén
field line eigenmode toroidal oscillations on different L-shells. The FLR
oscillations at the near-cusp L-shells are excited by the Alfvén impulse
associated with the convection disturbance followed after variations in
interplanetary parameters.

"Imaging of PSCs in 0-3 dimensions" by Carl-Fredrik Enell

The method generally used in studies of polar stratospheric clouds is
optical remote sensing from the ground, balloons or satellites. This
can be thought of as imaging in 0-3 dimensions depending on the technique
used and the corresponding geometry.
This seminar is indended as a discussion of the data we have available:
-Colour index
-Lidar
-Images
and the best ways to use and interpret these data, including some
mathematical problems encountered in the analysis.
Everybody is welcome to bring ther own pictures, lists of PSC observations,
and so on.

"Inertial Resistivity and Current Limitation in a Collision-free and Inhomogeneous Plasma" by Martin Bohm, Department of Space Physics, Umeå University, Kiruna

Measurements in space show that a collision-free plasma can support large potential drops. In interplanetary space collective processes, connected with plasma turbulence, can assume the roll of collisions. Inhomogeneous and collision-free plasmas may support large potential drops on the electron time scale even for free-streaming electrons in time-independent motion. This "inertial resistivity" has recently been used to interpret measured magnetic-field-aligned potential drops in the auroral zone of the Earth. In the seminar the results of one-dimensional particle-in-cell simulations of the response of an inhomogeneous plasma to a suddenly applied high voltage drop Va are presented. The results are compared with a theoretical model of the inertial conductance and with experiments. In the initial phase inertial conductivity dominates. Then the simulations show a sharp current drop associated with turbulence and reflection of current carrying electrons. In this case turbulent resistivity is the likely current limiting mechanism.

Autumn semester 2000

10 October 2000

Julien Forest, "Modelling of Spacecraft-Plasma Interactions (IPICSS Project): Introduction to the Particle-In-Cells method and Presentation of the PicUp3D/Spis system [Abstract]

11 October 2000

Dr. Alya Osepian, PGI Murmansk, "A pulsating regime of whistler cyclotron instability"

12 October 2000

Shu T. Lai, Space Vehicles Directorate, Air Force Research Laboratory, Hanscom AFB., MA, "Electron Temperature as a Key Parameter for Predicting Spacecraft Charging in Changing Space Weather" [Abstract]

17 October 2000

Rickard Lundin, "Planetary Plasma Acceleration Processes: Implications on Astrophysics" [Abstract]

26 October 2000

Yusuke Ebihara, "Wedge-Like Ion Dispersion in the Inner Magnetosphere: Viking Observation and Particle Simulation" [Abstract]

31 October 2000

Takayuki Kanda, "A brief introduction to our group in Tohoku University and my background in space physics" [Abstract]

7 November 2000

Uwe Raffalski, "The SOLVE/Theseo2000 ozone loss campaign in Kiruna during winter1999/2000. Part 1: An overview" [Abstract]

9 November 2000

Hans Nilsson, "EISCAT and DMSP observations of the quiet time evening sector ionosphere" [Abstract]

ABSTRACTS

Julien Forest, "Modelling of Spacecraft-Plasma Interactions (IPICSS Project): Introduction to the Particle-In-Cells method and Presentation of the PicUp3D/Spis system

The orbital structures (e.g. spacecraft) are in intimate interaction with the environment created by the space plasma. By simple contact, a large number of charged particles (electrons, ions) hit its external surface. Added to the ionisation effect by Sun UV or high energy particles, this leads to the accumulation of a net electrical charge on the spacecraft, inducing itself an electrostatic difference of potential between the satellite and the plasma.

This mechanism, called spacecraft-charging, and more generally the modifications of the spacecraft electrostatic environment, have many scientific and technological consequences, with sometimes as final conclusion the loss of satellite.

In the context of an European network, the IPICSS project, for Investigation of Plasma Induced Charging of Satellite Systems, had as objectives a complete analysis of these effects on modern satellites and scientific systems, including instrument calibration and in-flight interpretations. Its first goal was to find new mathematical models and test new numerical tools for more advanced and accurate simulations. This effort has led to the detailed study of the Particle-In-Cell (PIC), method initially issue from the hot plasma domain. This work was concretised be the development of a experimental simulation code, PicUp3D/Spis, based on a complete 3D PIC approach and fully written in JAVA. On a computing side, this effort of development has allowed to check in details the increasing possibilities of the JAVA language and the free, or open sources, softwares for intensive numerical simulations and scientific visualisation. The final results of the IPICSS project and the PicUp3D/Spis code are presented here. In addition, a discussion about these new computing approaches can be opened.

Shu T. Lai, Space Vehicles Directorate, Air Force Research Laboratory, Hanscom AFB., MA, "Electron Temperature as a Key Parameter for Predicting Spacecraft Charging in Changing Space Weather"

The space plasma electron temperature, Te, is a key parameter for predicting spacecraft surface charging. Two important properties are discussed: (1) the onset of spacecraft charging depends on a critical, or threshold, temperature, which depends on the surface materials, and (2) the approximately linear dependence of surface charging potential on the ambient plasma temperature in a Maxwellian space plasma. The onset of spacecraft charging in a Maxwellian space environment is independent of the ambient electron density, ion density, and ion temperature, but depends solely on a critical, or threshold, electron temperature. Below it, no spacecraft charging occurs; above it, spacecraft charging occurs. The current balance between the incoming and outgoing electrons gives an indeterminate spacecraft surface potential. The potential has to be determined by the balance between the incoming electrons, outgoing electrons, and the ambient ions. Other significant currents such as photo-electron or artificial beam emissions, if present, have to be included. The collection of currents by a spacecraft at geosynchronous altitudes is well described by the Langmuir probe formulation in the orbit-limited regime. That is, the spacecraft behaves like a Langmuir probe. Whereas the currents respond to an applied voltage on a Langmuir probe in the laboratory, the spacecraft potential V responds to the currents in space. For eV < kT, Taylor expansion of the current balance equation immediately gives the linear dependence of the spacecraft potential on the ambient electron temperature T, approximately. We present abundant evidences from ATS-5, ATS-6, LANL-90, LANL-94, and LANL-97 satellite data to support our contention of the two properties. Amazingly, surface potentials measured day after day on several satellite over several years confirm the existence of a critical temperature and the approximate linear dependence properties. We discuss limitations of the formulation. We also extend our discussion to non-spherical spacecraft geometry, double Maxwellian space plasma environments, including of photoelectrons, and beam emissions. Heretofore, photoelectron currents have been assumed to be one to two orders of magnitude larger than ambient electrons and ion currents. We explain physical mechanisms why only a small fraction of the photoelectrons can leave from a differentially and negatively charged spacecraft. Curve fitting using LANL-94 data shows that the fraction is indeed smaller than previously thought. Finally, we discuss the surprising good agreement between the Maxwellian theory and the satellite charging data.

Rickard Lundin, "Planetary Plasma Acceleration Processes: Implications on Astrophysics"

Contemporary space plasma physics have demonstrated that non-thermal energization and outflow of plasma is an important process for the loss of matter from celestial objects. The losses are due to internal processes, such as those occuring in stars like our own sun (the solar wind) or due to external/scavenging process by a stellar/solar wind impacting on neighbouring objects, e.g. comets, planets etc. Strongly magnetized objects, prohibiting a direct "scavenging" interaction, are losing matter by a process denoted charge exchange. Charge exchange is a process where energetic ions become neutralized by interacting with neutral atoms, thererby producing fast neutral atoms. In this way a fast "wind" of energetic neutrals is produced by hot plasma interacting with a neutral gas. Charge enchange have long been known to represent a major loss process for "stably" trapped energetic ions in planetary magnetospheres such as those for the Earth, Jupiter and Saturn. In this way one may consider planetary magnetospheres as objects "radiating" energetic neutral atoms into space.

In this report we consider other celestial objects such as stars and galaxies and compare them with planetarys magnetospheres. We point to the fact that stars and galaxies are also likely to "shine" of energetic neutral atoms. Depending on the locus of observation an observer will experience a blueshift or redshift of the light emitted/absorbed by the neutral wind. For instance, the Lyman alpha emissions from the wind of neutral hydrogen emitted from the Sun by charge exchange will be primarily redshifted, except in the direction pointing directly towards the Sun. The net outward wind of ENA:s from the ensamble of stars within a galaxy is expected to lead to a similar results for an observer situated within the galaxy, that is primarily a redshift of emission/absorbtion lines from the expanding neutral wind.

Although the galactic ENA-wind is not the only factor leading to a redshift of astrophysical objects outside our own galaxy, it yet remains an important factor that must be considered when discussing dopplershifted absorbtion and emission lines. We will present examples of stars and galaxies where this is quite obvious.

Yusuke Ebihara, "Wedge-Like Ion Dispersion in the Inner Magnetosphere: Viking Observation and Particle Simulation"

In the dayside inner magnetosphere, Viking ion detectors often observed
dispersed structures of sub-keV ions ("wedge-like" dispersion), which had
not been understood well. We have proposed a possible process producing them
by means of a single particle simulation. Finally, they are found to be
results of temporal and spatial changes in the density (or temperature)
structure in the nightside plasma sheet. This analysis will enable us to
monitor remotely variations of density(temperature) structure in the
near-earth plasma sheet if this method is valid and established.

Takayuki Kanda, "A brief introduction to our group in Tohoku University and my background in space physics"

The seminar will be a short introduction to our laboratory's works and my background in space physics in order to have you know the phenomena, which I have been interested in and I have studied, before I start my work at IRF.

Division of Space Physics in Tohoku University is one of the largest space-research organizations in Japan, which consists of four groups, electromagnetism of Space and Earth Group, Planetary Atmosphere Physics Group, Planetary Radio Wave Science Group, and Planetary Optical Emission Science Group. The latter two groups are parts of Planetary Plasma and Atmospheric Research Center (PPARC), which was established in April 1999. We research a variety of phenomena from the atmosphere up to space in the solar system, such as airglow, aurora, planetary atmosphere, planetary radio waves/optical emissions, and so on.

I am a currently graduate student in Master's programme and a member of Planetary Radio Science Group in PPARC. In the talk I would like to review our group's works and my studies. Our common purpose is to reveal the physical processes produced in planetary plasma and atmosphere by observations of planetary radio waves and using data measured by spacecrafts, and our targets are mainly the electro-magnetic dynamics, acceleration process of energetic particles, and auroral phenomena (including studies on related plasma waves and particles) in the terrestrial and Jupiter's magnetosphere. I would like to present some topics of them, that is, observations of the decimeter radio waves which are generated by synchrotron radiation from relativistic electrons in the inner Jovian magnetosphere, the dynamics of energetic electrons in the radiation belt during geomagnetic storms, and the morphological study on black aurora.

I began to study electron acceleration mechanisms this spring, and I have been very interested in suprathermal electron bursts phenomena(STEB) which might be related to black aurora in the low-altitude region. Therefore I am just looking through all electron data measured by Freja satellite and searching for interesting events such as STEB.

Uwe Raffalski, "The SOLVE/Theseo2000 ozone loss campaign in Kiruna during winter1999/2000. Part 1: An overview"

This presentation addresses the interested audience even with little
knowledge on stratospheric research. I will present a general overview
over the campaign without going into technical details of instruments
and techniques involved. I will rather present basic information, for
instance the the climatology of the winter, the development of the
vortex and some interesting measurements from the campaign. The
collected data show a significant ozone depletion during the course of
the winter. This will be presented and compared to earlier winters.
Since the role of polar stratospheric clouds has been studied during the
winter, some of the findings will be presented here as well, not without
showing some nice pictures from January and February, when there were
strong PSC events.

A second part of this presentation will be given later in the year with
some more detailed discussion of certain measurements and findings and
it will address to the even more interested audience.

Hans Nilsson, "EISCAT and DMSP observations of the quiet time evening sector ionosphere"

A combination of EISCAT CP-3 data (latitude scans) and DMSP
observations of charged particle precipitation has been used to study
the structure of the evening sector auroral and subauroral
ionosphere. We seek to establish the interrelationship between
electric fields, conductance structures, F region structures (i.e.
the trough) and proton precipitation. In particular we try to compare
the most common explananation for the formation of the main
ionospheric trough, that through the decay of F region plasma due to
long residence time in darkness, with the theory for auroral cavity
formation in which F region thermal plasma carries a downward
field-aligned current (FAC) which leads to an evacuation of E and F
region plasma in the current region. The region of downward FAC in
the evening sector (i.e. the region 2 current) is also associated
with proton precipitation. We show how most proton precipitation
regions are closely associated with the most equatorward region of
wesward flows, i.e. northward electric fields, in the auroral
ionosphere. The proton precipitation is charge exchange spread, and
it is experimentally shown how large this spread is, and how the
resulting conductance structure is smoothly spread into the lower
latitude region with low flows (i.e. corotating ionospheric plasma).
This spread allows for a smooth and simple relation beween the
electric field and associated field-aligned currents. We discuss
whether the existence of proton precipitation in association with the
trough can be used to diagnose the convective history of the plasma
in the trough (with we I mean all of us attending the seminar).
Finally, can we say something about the proton precipitation? Why are
the proton scattered into the loss cone and precipitated? Can this
dataset give a clue?

GENERAL SEMINARS, Spring Semester 2000

23 May 2000

"My experience as an environmental researcher", by Sachiko Joki

9 May 2000

Henrik Svensmark, Danish Space Research Institute [Abstract]

2 May 2000

"What does a single number say about a winter's ozone depletion?" by Johan Arvelius [Abstract]

4 April 2000

"Some aspects on Incoherent-Scatter Radars" by Micce Hedin [Abstract]

28 March 2000

"Some notes about past, present and future Ionosondes in Sweden" by Christer Jurén [Abstract]

21 March 2000

"Why study IRF? A presentation of Science & Technology Studies(STS)" by Marta Nyborg, Linköping University [Abstract]

14 March 2000

"Global atmospheric electric circuit and geomagnetic substorm interrelation: a possible new link between solar and terrestrial phenomena?" by Evgenia Belova [Abstract]

7 March 2000

Olle Norberg

29 February 2000

"Climate forcing by anthropogenic aerosols", by Robert Charlson, USA

15 February 2000

Winter Cities Conference in central Kiruna

8 February 2000

Yasuhito

1 February 2000

Tima Sergienko

24 January 2000

"The cusp as seen from Interball" by Ingrid Sandahl [Abstract]

11 January 2000

"Direct plasma acceleration by the radiation?" by M. Yamauchi [Abstract]


SPACE PLASMA SEMINARS, Spring Semester 2000

6 April 2000

"Radar Micrometeors studies at Arecibo - an overview" Diego Janches, USA [Abstract]

23 March 2000

"What is the big difference between biological and technical image processing?" Thomas Lindblad, KTH [Abstract]

10 February 2000

"Dynamic Trapping of Electrons in Space Plasmas" by Martin Bohm [Abstract]

27 January 2000

Ingemar Häggström


* To confirm dates and seminar-holders, contact the seminar co-ordinator, Bruno Aparicio, bruno.aparicio@irf.se (tel. +46-980-79086) *


ABSTRACTS

Henrik Svensmark, Danish Space Research Institute

Satellite data have revealed a striking correlation between the intensity of galactic cosmic rays (GCR) and low liquid clouds ( < 3 km). GCR is responsible for nearly all ionisation in the atmosphere below 35 km. However, a direct link between GCR and cloud formation is yet to be unambiguously established and, moreover, the microphysical mechanism is not understood. One mechanism could involve aerosol particles (0.001- 1 mu in diameter) and the formation of cloud condensation nuclei (CCN). A systematic variation in the properties of CCN will affect the cloud droplet distribution and thereby influence the radiative properties of clouds. If the GCR/Cloud link is confirmed, variations in galactic cosmic ray flux, caused by changes in the solar activity could influence Earth's radiation energy budget. In particular the magnetic flux carried by the solar wind has more than doubled during the last 100 years, at the same time as the global temperature has risen.

In the talk we will show a few examples that demonstrate remarkable correlation between solar activity and climate. The possible link between solar activity and clouds will be discussed. Finally plans to test the link under controlled laboratory conditions in a particle beam at CERN with a cloud chamber, will be presented.

"What does a single number say about a winter's ozone depletion?" by Johan Arvelius

In a pressrelease from the European Commission's Research Directorates-General we could all read that there has been an ozone-loss of 60% at 475K level this season.
Ozone depetion over a large area and a full season is a quite different task to deal with. Estimations of the chemical depletion of ozone in the arctic over the winter is a complex and burning research topic involving a lot of different mesurements and simulation.
The seminar will be a short review of polar atmospheric science mainly at stratospheric levels under winter conditions.
The headlines from last week that talked about 60% ozone depletion at certain heights will be discussed and I hope you should get a more realistic picture of this year's ozone depletion.

"Radar Micrometeors studies at Arecibo - an overview" by Diego Janches, USA

UHF radar meteor observation have seen a rebirth after almost 30 years
(Evans, J. Geophys. Res., 70, 1965) starting with the pioneering work of
Pellinen-Wannberg and Wannberg (J. Geophys. Res., 99, 1994). Following
this work, a similar line of research grew at Arecibo Observatory (AO)
from incoherent scatter radar observations of the ionosphere, where
meteors were simply treated as measurement-noise, to a distinctly
different scientific focus. Data-taking and analysis capabilities
reached a high enough degree of sophistication that meteors could be
observed with the current 150 m and 1 ms range and time resolutions,
respectively, at the 430 MHz radar frequency. These measurements are
very distinct from the classical HF/VHF radar observations in that the
head-echo (radar scattering from the region immediately surrounding the
meteoroid) is always observed leading uniquely to very accurate speed
determinations. We have developed a multi-pulse Doppler technique that
permits the direct measurement of Doppler velocities from the
micrometeor leading-edge (or head-echo) and in some cases micrometeor
deceleration. The realization of highly resolved meteor altitudes,
velocities and deceleration are crucial for understanding a number of
aeronomical and astronomical problems. Particle sizes and masses can be
estimated from these results, which are needed to estimate the meteoric
mass flux in the upper atmosphere. Extra-atmospheric speed can also be
determined if the mass-loss mechanisms that these particles undergo are
understood. These speeds are essential for the determination of dust
orbital parameters. More than 7000 and 3000 events detected during the
Leonids 1997 and 1998 period respectively were so far analyzed.
Approximately 10% of these manifest deceleration. An overview of the
results obtained so far is discussed.

"Some aspects on Incoherent-Scatter Radars" by Micce Hedin

I will present and discuss selected parts from the theory of IS-radars
(eg EISCAT). The focus will be put on parts where approximations are
done, and where a priori assumptions are made about the ionosphere.

"Some notes about past, present and future Ionosondes in Sweden" by Christer Jurén

In the past Sweden had a well-known reputation in shortwave sounding of
the ionosphere. The sounding had its culmination during the 60's. The first
ionosondes in Sweden were built during the 40's by two almost independent
groups: one scientific and one which focused on prognosis service for
shortwave propagation. Today all ionosondes in Sweden are handled by the
Swedish Institute of Space Physics with its headquarters in Kiruna. They
are mainly used in connection with aurora research but data are also sent
all over the world for use in space weather prognoses and in prognosis of
the state of the ionosphere related to short radio wave propagation.
The above is described with the help of audio-visualisations on a computer
connected to the Net.
The theory of radio wave propagation in the ionosphere is discussed from an
historical point of view as an introduction to the modern development of
the shortwave sounding of the ionosphere over Sweden.
Finally the relation to other similar instruments in the world,
Dynasondes, Digisondes, Candi etc., is described together with the
planned sounding activity in Sweden during the next solar cycle (the year
2000).
"What is the big difference between biological and technical image processing?" Thomas Lindblad, KTH
Even small kids can see if there is an animal in a picture flashed during
20 ms while a computer easily mistakes some sunflowers for a tiger. So
what is the big difference between biological and technical image
processing? After all the "speed" of becoming aware of things, i.e the
operations in the visual cortex, is only slightly higher than "video rate"
The answer is that the processing is done in a very cleaver manner in the
mid-brain. One typical thing is that there are more feedback signals than
feedforward signals. Perhaps there is one or two lessons to be learnt for
the next generation of smart sensors.

"Why study IRF? A presentation of Science & Technology Studies(STS)" by Marta Nyborg, Linköping University

Jag kommer från Linköpings Universitet och har varit här sedan januari. Jag
gör en studie på IRF som ingår i mitt avhandlingsprojekt "Från pojkdröm
till könsblandad vetenskap - svensk rymdforskning". (Med "svensk
rymdforskning" menas också atmosfärsforskning!).
På seminariet kommer jag att prata lite om min hemmainstitution, Tema i
Linköping; den samhällsvetenskapliga forskningstradition som jag tillhör
(STS); genus (= "det socialt konstruerade könet")/vetenskap/teknik och till
slut en del om varför jag valde IRF som plats för min fältstudie.

"Global atmospheric electric circuit and geomagnetic substorm interrelation: a possible new link between solar and terrestrial phenomena?" by Evgenia Belova

The modern scientific point of view on the global atmospheric electric
circuit will be presented. The three main generators, or energy sources, of
this circuit are believed to be thunderstorms, the ionospheric dynamo
(tides) and the solar wind/magnetosphere dynamo. Thunderstorms, which occur
mostly at equatorial and subequatorial latitudes maintain the potential
difference of 150-600 kV between the ground and the ionosphere. Tides in
the ionosphere lead to the appearance of a horizontal potential difference
of 5-15 kV between high and low latitudes at ionospheric heights. Solar
wind-magnetosphere coupling results in an additional ionospheric potential
drop of 40-100 kV across the polar caps. Main attention in this
presentation will be paid on contribution of the solar wind/magnetosphere
dynamo generator into this electric system.
The geomagnetic substorm is a common phenomenon at high latitudes. The
distribution of the ionospheric electric field and conductivity are known
to change in characteristic ways during substorms, so substorms could
provide an additional ionospheric source of large enough horizontal scale
to contribute to the local atmospheric electric current.
We have analysed air-earth vertical currents (AECs) measured by a long wire
antenna at Esrange, northern Sweden during 35 geomagnetic substorms. Using
superposed epoch analysis we compare the air-earth current variation during
the 3 hours before and after the time of the magnetic X-component minimum
with that for corresponding local times on 35 days without substorms. After
elimination of the average daily variation we can conclude that the effect
of substorms on AEC is distinguishable but small. During about 2 hours
before the time of geomagnetic X-component minimum, the AEC increases
probably due to enhancement of the ionospheric electric field. To explain
these results we analyse the data on ionospheric electric field measured by
STARE above Tromso, Norway. The results of analytical modelling will also
be presented.
Because the geomagnetic substorms are associated with changes in the
interplanetary magnetic field, the obtained effect in AEC could be
considered as one more channel for solar-atmospheric interaction. Different
others suggestions on the role of the global atmospheric circuit in
relation between solar variability and climate will also be discussed.

"Dynamic Trapping of Electrons in Space Plasmas", by Martin Bohm

The neutralization of positive space charge is studied in a case where
heavy positive ions are added to a limited region of length L in a
collisionfree magnetized plasma. It is found that electrons which become
accelerated towards the positive space charge can only achieve a partial
neutalization: they overshoot, and the positive region becomes surrounded
by negative space charges which screen the electric field from the
surroundings. The process is studied both analytically and by computer
simulations with consistent results: large positive potentials (U>>kte/e)
can be built up with respect to the surrounding plasma. In the process of
growth, the potential maximum traps electrons in transit so that
quasineutrality is maintained. The potential U is proportional to the
ambient electron temperature and the square of the plasma density increase,
but independent of both the ion injection rate and the length L.
The process explains several features of the Porcupine xenon beam injection experiment.

"The cusp as seen from Interball" by Ingrid Sandahl

The Interball project is very well suited for cusp/cleft studies. Interball-Tail and its subsatellite Magion-4 visit the cusp at several altitudes, and also traverse the external cusp during both quiet and disturbed conditions, while Interball-Auroral and Magion-5 cross the cusp at lower altitudes. In this paper, cusp results from Interball will be reviewed and some new observations will be presented. The data from Interball show that the cusp is always a clearly distinguishable feature, but that the location of the external cusp, as well as the plasma behavior changes dramatically with solar wind condi-tions. A number of different entry mechanisms are supported by the data, including sub-solar point recon-nection, high latitude flank reconnection leading to entry along open field lines at high latitude, lobe re-connection, and direct entry through the turbulent, low-B-field outer cusp region. Plasma entry from high lati-tudes seems to be more important than thought earlier. The plasma flow in the magnetosheath outside the cusp displays a complicated pattern and high latitude lobe field lines are strongly indented.

"Direct plasma acceleration by the radiation?" by M. Yamauchi

Although the solar radiation carries 1000 times more momentum than the
solar wind at 1 AU, the direct solar wind acceleration by photon has been
considered negligible because the cross section of the Thomson scattering
is extremely small.
However, the theory of the Thomson scattering is not perfect because the
effect of the plasma state has not been included. Since a simple
displacement of a charged particle causes a shift of electric potential
which is comparable to the energy of the incident wave (1-10 eV), the
collision cross section might be enhanced if we consider the plasma state
and background electric/magnetic field, e.g., via transient absorption
through which the radiation looses very little energy.
So far no laboratory experiment examined such scenario.
Therefore, it is worth while to examine the conditions/consequences for
direct acceleration of protons and electrons by the UV and visible light.
If this process works, it might explain :
(1) additional substantial momentum flux of the solar wind;
(2) lower solar constant during the solar maximum than during the solar
minimum;
(3) fast solar wind flow from the coronal hole;
(4) a part of the angular momentum of the super-rotation of Venus upper
atmosphere; and
(5) a part of the red-shift of spectrum from distant galaxies.
The last consequence requires revision of the Hubble constant.

AUTUMN 1999

14 December 1999

"Ring current proton precipitation and its consequence to the ionosphere" by Yusuke Ebihara [Abstract]

25 November 1999

" Source and loss processes of magnetospheric plasma" by Bengt Hultqvist

23 November 1999

"Artificial airglow and analysis of ALIS data" by Björn Gustavsson [Abstract]

16 November 1999

Seminarium: Origin of Life, Hans Nilsson och Ingrid Sandahl [Abstract]

11 November 1999

"Meteorskur värdig millennieskiftet?" by Asta-Pellinen-Wannberg [Abstract]

9 November 1999

"ENA Imaging of Planetary Magnetospheres" by Pontus C:son Brandt [Abstract]


ABSTRACTS

"Ring current proton precipitation and its consequence to the ionosphere" by Yusuke Ebihara

EISCAT incoherent radar measurements are compared with precipitating particle data from Viking and DMSP satellites and numerical simulations to reveal a role of the precipitating ring current protons (1-100 keV) to electron production in the auroral E region. It has been pointed out that precipitating protons enhance significantly the electron density in the auroral E region as compared with that due to precipitating electrons. However the spatial and temporal variation of the ionization structure due to precipitating protons has not yet been understood. We simulate the motion of ring current protons and calculate the precipitating proton flux. If we assume that the trapped protons are scattered into the loss cone with a characteristic time scale of the strong diffusion limit, the results fairly account for the lower latitude portion of the ionization structure measured by EISCAT.

"Artificial airglow and analysis of ALIS data" by Björn Gustavsson

Today's seminar will show the observations of artificially enhanced airglow produced by the EISCAT-Heating facility in Tromsø. Detailed image analysis can reveal some physically interesting charateristics of the enhanced airglow, such as:

The current theories will be compared with the ALIS observations.

Seminarium: Origin of Life, report by Hans Nilsson och Ingrid Sandahl

Some thoughts, notes and impressions from the Origin of Life workshop in Sigtuna 27 - 29 October and a discussion on if and how IRF and space physics can contribute to the subject. Rosetta and Mars Express were the two future missions where IRF Kiruna participates which were most frequently mentioned during the workshop. Yama and Jan-Erik Wahlund (Cassini) have been thinking about 'homochirality', and Yama has proposed possible future balloon missions.

"Meteorskur värdig millennieskiftet?" by Asta-Pellinen-Wannberg

Natten till den 18 november återkommer meteorskuren Leoniderna. En meteorskur uppträder när jorden går igenom en kometbana och träffas av utspridd kometstoft. Leonidernas moderkomet är 55P/Tempel-Tuttle med 33-års period, och den besökte det centrala solsystemet på våren 1998. År 1833 bjöd Leoniderna på det mäktigaste naturliga fyrverkeriet som någonsin observerats med miljontals stjärnfall under några intensiva timmar.

Troligtvis kommer vi inte att uppleva något så intensivt i år, men det är kanske ändå den bästa chansen i vår livstid. Prognoserna för årets meteorsvärm varierar kraftigt. Vissa experter påstår att aktiviteten skulle ha varit som högst 1998, andra menar att den maximerar i år. Man förväntar sig allt från inga förhöjda flöden alls upp till 100 000 meteorer per timme. Före fjolårets Leonidsvärm bröt full panik ut i världens stora rymdorganisationer då man insåg att den jordnära rymden skulle fyllas av stoft som närmade sig jorden med 70 kilometer i sekunden. Kanske dels på grund av alla försiktighetsåtgärderna rapporterades inga skador på satelliter, men det observerade meteorflödet var inte heller speciellt högt - bara några hundra per timme som bäst. Fjolårets erfarenheter och resultat diskuteras, årets planerade mätningar samt förväntningar så väl för gemene man som forskare och satellitoperatörer kommer att spekuleras.

"ENA Imaging of Planetary Magnetospheres" by Pontus C:son Brandt

What do we mean by "imaging" and why is it important? And what are "ENAs" and what makes them so special in magnetospheric physics? These questions will be answered and not until the audience understands the answers I will give glimpse of the results from the microsatellite Astrid-1 and some of the simulation results from Mercury. If time permits, additional ENA sources will be discussed.


AUTUMN 1998

IRF popular or general seminar
IRF plasma seminar (PS)
IRF atmospheric seminar (AS)

02/09 8:45-17:20 ENA imaging at Mars. Workshop
03/09 09:00-17:55 ENA imaging at Mars. Workshop
08/09 Dr. Uwe Feucht, German Space Operations Center Section Space Flight Dynamics
10/09 Kerstin Stebel (AS)
15/09 Mikael Hedin
17/09 PS: Plasma conference reports
Laila Andersson
Yamauchi
Solveig Kjus
24/9 Sheila Kirkwood (AS)
25/09 Sheila Kirkwood Professorsinstallation
29/09 Assar Westman (popular seminar)
01/10 Solveig Kjus (PS)
06/10 Pontus C:son Brandt, Overview of Basic Plasma Theory - Review of the Culham Summer School in Plasma Physics
08/10 Uwe Raffalski (AS)
13/10 Barbara Popielawska
15/10 Björn Gustavsson (PS)
20/10 Sten Yngström
22/10 Carl-Fredrik Enell (AS)
29/10 Laila Andersson (PS)
03/11 Urban Brändström
10/11 Asta Pellinen-Wannberg (popular), Leonids are coming!!!
12/11 Ulrik Eklund (PS)
19/11 Johan Arvelius (AS)
24/11 Arndt Meier (popular), Vetenskap ur fågelperspektivet
01/12 Martin Bohm
03/12 Arndt Meier (AS), Results from the NDSC intercomparison and some recent work
10/12 Hans Nilsson (PS)
15/12 Mats Holmström (popular)
17/12 Khaled Fadel (AS)

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Updated by
2005-07-13