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| 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. |
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.
| 22 January (Aula) | Dr Uwe Raffalski (IRF-K), Odin’s future: STEAM ? - A new Swedish Satellite for the Investigation of Earth’s Atmosphere. [Abstract] |
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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] |
AbstractsDr Uwe Raffalski (IRF-K), Odin’s future: STEAM ? - A new Swedish Satellite for the Investigation of Earth’s Atmosphere.
Dr Georgy Zastenker (Space Research Institute, Moscow), Review of some new solar wind features investigated by Interball project.
Dr Edmond Murad (Emeritus, Space Weather Center of Excellence, Air Force Research Laboratory, Hanscom AFB, MA, USA), Melting and Evaporation of Meteoroids.
Dr Masatoshi Yamauchi (IRF-K), Wedge-like structured sub-keV ions inside the ring current region.
Prof. Rickard Lundin (IRF-K), Solar wind removal of volatiles from celestial objects - perspectives on the Mars Express- and Rosetta missions.
Dr Alexander Kozlovsky (Sodankyla Geophysical Observatory, Finland), Response of Dayside Auroras and Ionospheric Plasma Flows to a Solar Wind Pressure Pulse.
Dr Vladimir Safargaleev (Apatity), The objectives and some preliminary results of EISCAT campaign on investigation of dayside auroras dynamics.
Dr Evgenia Belova (IRF-K), Polar Mesosphere Summer Echoes and ionospheric heating: results and future plans.
Dr Yasuhide Hobara (IRF-K), High Altitude Oxygen Outflow Observed by Cluster Satellites: Energization and Subsequent Wave Activities (Preliminary Results)
Dr Herbert Gunell (IRF-K), Solar wind charge exchange at Mars.
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).
Grigory Nikulin (IRF-K), The Mean Meridional Circulation and Wintertime Ozone Buildup in Midlatitudes.
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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] |
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11 September |
Prof. Dr Ingrid Mann (Institut für Planetologie, Westfälische Wilhelms-Universität, Germany), The Heliosphere and the Meteoritic Complex. [Abstract] |
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18 September |
Prof. Bengt Hultqvist (IRF-K), Downward Accelerated Ions: Acceleration Mechanism and Ion Source. [Abstract] |
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25 September |
Prof. Rickard Lundin (IRF-K), Plasma in the magnetospheric boundary layers: Frozen in - or not? [Abstract] |
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2 October |
Magnus Emanuelsson (IRF-K), Strålningstest av OpAmpar. [Abstract] |
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Mon. 13 October, 10 am (Aula) |
Dr Evgenia Belova (IRF-K), How and why we heat the ionosphere. (Docent lecture) |
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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] |
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23 October |
Dr Mats Holmström (IRF-K), Monte Carlo simulations of planetary ions and neutrals at Mercury. [Abstract] |
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30 October |
Grigory Nikulin (PhD student, IRF-K), Influence of early winter wave activity on midwinter circulation in the stratosphere and troposphere. [Abstract] |
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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] |
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13 November |
Dr Peter Dalin (IRF-K), The comparison of Danish and Moscow NLC observations: statistical results. [Abstract] |
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20 November |
Dr Hans Nilsson (IRF-K), Radar Observations in the Vicinity of Pre-noon Auroral Arcs. [Abstract] |
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4 December (Aula) |
Walter Allvin (Zero Group) presents Xero and the Zero Group's activities (in the Aula): www.xero.se |
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11 December |
Dr Tima Sergienko (IRF-K), The lateral spread of proton precipitation: A comparison between incoherent scatter radar observations and model. [Abstract] |
ABSTRACTS
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.
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.
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.
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.
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.
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.
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.
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.
P. Dalin, S. Kirkwood, H. Andersen, O. Hansen, V. RomejkoSystematic 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.
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.
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]
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16 January |
Sven Bugarski (University of Heidelberg), Methods and Problems of BrO DOAS Analysis. [Abstract] |
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7 February |
Mats André (IRF Uppsala), Layers at ion and electron scales in the high-latitude magnetopause. |
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11 February |
Dr Takumi Abe and Dr Takeshi Imamura (Japan), Japanese Venus Climate Orbiter. |
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13 February |
Evgenia Belova (IRF-K), A Study of Polar Mesosphere Summer/Winter Echoes with the EISCAT VHF Radar. [Abstract] |
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20 February |
Vladimir Safargaleev (Polar Geophysical Institute, Apatity, Russia), High-latitude dayside Pc1 events as indicator of reconnection. [Abstract] |
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27 February |
Rickard Lundin (IRF-K), The Wakes and Magnetotails of Venus and Mars. [Abstract] |
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13 March |
Grigory Nikulin (IRF-K), Dynamical contributions to the total ozone trends in the Northern Hemisphere midlatitude. [Abstract] |
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20 March, 1 p.m. |
Sheila Kirkwood (IRF-K), Dust in the mesosphere - is it really there and why should we care? [Abstract] |
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27 March |
Susanne Roslin (Umeå University), Adsorbtion of CFC on Carboxen during sampling in the stratosphere. [Abstract] |
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3 April |
Peter Dalin (IRF-K), The observation of gravity waves in Noctilucent Clouds. [Abstract] |
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10 April, 1 p.m. |
Asta Pellinen-Wannberg (IRF-K), The EISCAT meteor method: a review and recent results. [Abstract] |
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Tues. 22 April, 10 a.m. |
Hans Nilsson (IRF-K), Cluster multi-point observations of ion outflow. [Abstract] |
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8 May |
No seminar (Rymdforum 03 conference in Kiruna) |
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15 May |
Csilla Szasz and Johan Kero (IRF-K), A Solar Active Region Quasi-Biennial Fluctuation. [Abstract] |
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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] |
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5 June |
Jane Zheng-Johansson (IOFPR, Nyköping), Unification Scheme for Classical and Quantum Mechanics at All Velocities. [Abstract] |
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12 June |
Herbert Gunell (IRF-K), Simulated ENA images of the Venus-solar wind interaction region. [Abstract] |
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19 June |
Tima Sergienko (IRF-K), Quenching rates of O(1D) in the upper thermosphere. [Abstract] |
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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: [TOP] "High-latitude dayside Pc1 events as indicator of reconnection", Vladimir Safargaleev (Polar Geophysical Institute, Apatity, Russia)
"The Wakes and Magnetotails of Venus and Mars", Rickard Lundin (IRF-K)R. Lundin and S. Barabash "Dynamical contributions to the total ozone trends in the Northern Hemisphere midlatitude", Grigory Nikulin (IRF-K)
"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). "Adsorbtion of CFC on Carboxen during sampling in the stratosphere," Susanne Roslin (Umeå University)
[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 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. "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. "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. "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. |
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3 October |
Carl-Fredrik Enell (IRF-K), Optical Studies of Stratospheric Clouds. [Abstract] |
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17 October |
Narayana Rao (IRF-K), UTLS Ozone Variations over Northern Europe. [Abstract] |
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24 October |
Johan Arvelius (IRF-K), The Problem of Identifying Tropopause Folds in Ozone Soundings Avoiding Seasonal Biases. [Abstract] |
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14 November |
Peter Dalin (IRF-K), An Estimation of Inertio-Gravity Wave Parameters in Noctilucent Clouds. [Abstract] |
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21 November |
Sachiko Joko (IRF-K), Ionospheric Ions Outflowing at High Altitudes in the Dayside Magnetosphere. [Abstract] |
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Tuesday 26 November |
Rickard Lundin (IRF-K), Ponderomotive Forces in the Magnetosphere. [Abstract] |
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5 December |
Herbert Gunell (IRF-K), Beam-Plasma Interaction. [Abstract] |
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12 December (10-10.30) |
Professor Liu (Center for Space Science and Applied Research, China), A Brief Introduction to the Chinese Double Star Project. |
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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. |
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12 December (11-11.30) |
Pontus C:son Brandt (Applied Physics Laboratory, USA), Usefulness of ENA Imaging for Magnetospheric Research: New IMAGE Results. |
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19 December |
Khaled Fadel (IRF-K) |
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Friday 20 December |
Gösta Gahm (Dept of Astronomy, Stockholm University), The Architecture of Interstellar Clouds. |
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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)
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4 February |
"Kan man höra norrskenet? Den naturvetenskapliga bakgrunden till ljudfenomen i samband med starka norrsken". Seminar by Christer Jurén, IRF Kiruna. |
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14 March |
"Observations and Analysis of Artificial Aurora". Seminar by Björn Gustavsson, National Institute of Polar Research, Tokyo, Japan. |
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21 March |
"Case Studies of the Dynamical Development of Polar Stratospheric Clouds Using Multistatic Imaging". Seminar by Carl-Fredrik Enell, IRF Kiruna. [Abstract] |
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28 March |
"Locations of proton isotropic boundaries as measured by conjugate high-altitude and low-altitude satellites". Seminar by Natalie Ganushkina, FMI. [Abstract] |
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9 April |
"Substorm results from Interball" and a report from the substorm conference in Seattle by Ingrid Sandahl, IRF Kiruna. |
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11 April |
"Cluster high-altitude observations of ionospheric plasma outflow". Seminar by Sachiko Joko, IRF Kiruna [Abstract] |
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18 April |
"Response of Polar Mesosphere Summer Echoes to Ionospheric Heating". Seminar by Evgenia Belova, IRF Kiruna. [Abstract] |
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2 May |
"Trends in Moscow NLCs occurrence and brightness." Seminar by Petr Dalin, IRF Kiruna. [Abstract] |
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16 May |
"Aerosols, clouds and climate." Seminar by Johan Arvelius, IRF Kiruna. [Abstract] |
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21 May |
"Longtime DOAS observation of trace gases in Kiruna." Seminar by Thomas Wagner, Heidelberg, Germany. |
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30 May |
"Auroral radiation of Jupiter." Seminar by Anil Bhardwaj, Space Physics Laboratory, Vikram Sarabhai Space Centre, India. |
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31 May |
"Space Program of India." Seminar by Anil Bhardwaj, Space Physics Laboratory, Vikram Sarabhai Space Centre, India. |
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4 June |
"Fast volume rendering." Seminar by Mats Holmström, IRF Kiruna. [Abstract] NB: in the Aula. |
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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. |
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ABSTRACTS "Case Studies of the Dynamical Development of Polar Stratospheric Clouds Using Multistatic Imaging". Seminar by Carl-Fredrik Enell, IRF Kiruna.
"Locations of proton isotropic boundaries as measured by conjugate high-altitude and low-altitude satellites". Seminar by Natalie Ganushkina, FMI.
"Cluster high-altitude observations of ionospheric plasma outflow". Seminar by Sachiko Joko, IRF Kiruna.
"Response of Polar Mesosphere Summer Echoes to Ionospheric Heating". Seminar by Evgenia Belova, IRF Kiruna.
"Trends in Moscow NLCs occurrence and brightness." Seminar by Petr Dalin, IRF Kiruna.
"Aerosols, clouds and climate." Seminar by Johan Arvelius, IRF Kiruna.
"Fast volume rendering." Seminar by Mats Holmström, IRF Kiruna.
"Waves and Fluctuations in Non-Maxwellian Plasmas." Seminar by Herbert Gunell, Dept. of Physics and Astronomy, University of Iowa.
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23 August |
Evidence for impulsive solar wind plasma penetration through the dayside magnetopause, Rickard Lundin, IRF [Abstract] |
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30 August |
Recent Cluster CIS (Cluster Ion Spectrometry) results, Rickard Lundin, IRF |
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11 September |
Comment on V.M.Vasyliunas, "Electric field and plasma flow: What drives what". Seminar by M. Yamauchi, IRF [Abstract] |
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23 October |
The Use of Stratosperic Tracer-Interrelationships to study chemical reactions in the Spring Polar Vortex. Seminar by Johan Arvelius, IRF [Abstract] |
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30 October |
First results from RAPID on Cluster. Seminar by Ingrid Sandahl, IRF [Abstract] |
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1 November |
Analysis Technique School for Space Plasma Data. Seminar by Sachiko Joko [Abstract] |
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6 November |
Fast neutral atom imaging: A journey to Mars, Mercury, and back. Seminar by Mats Holmström [Abstract] |
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15 November |
The Munin Plasma Data. Seminar by Kan Ogawa [Abstract] |
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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) |
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27 November |
Fine structure of the diffuse auroral zone observed simultaneously by ALIS and the FAST satellite. Seminar by Tima Sergienko. |
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29 November |
Cosmic Dust Measurements with HPLA radars. Seminar by Asta Pellinen-Wannberg. |
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4 December |
Are there clouds in the winter mesosphere? Seminar by Sheila Kirkwood. [Abstract] |
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11 December |
En kamera är väl en kamera? Ett seminarium om äpplen och päron. Seminar by Urban Brändström [Abstract] |
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.
First results from RAPID on Cluster. Seminar by Ingrid Sandahl, IRF Kiruna
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
Fast neutral atom imaging: A journey to Mars, Mercury, and back. Seminar by Mats Holmström, IRF Kiruna
The Munin Plasma Data. Seminar by Kan Ogawa (Japan)
Framtiden för IRF:s jonosonderingar med anledning av ett nytt anslag på 890 tkr från Kempestiftelserna. Seminar by Christer Jurén, IRF Kiruna
Are there clouds in the winter mesosphere? Seminar by Sheila Kirkwood, IRF Kiruna
En kamera är väl en kamera? Ett seminarium om äpplen och päron. Seminar by Urban Brändström, IRF Kiruna
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11 January 2001 |
"Modelling small-scale mountain lee-waves over Kiruna", by Sheila Kirkwood, IRF, Kiruna [Abstract] |
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16 January 2001 |
"The Munin Project", by Olle Norberg, IRF, Kiruna |
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13 February 2001 |
"Simulations of Charge-Exchange Processes near Mars", by Mats Holmström, IRF, Kiruna [Abstract] |
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15 February 2001 |
"The Physics of the Cusp from an Interball Perspective", by Ingrid Sandahl, IRF, Kiruna [Abstract] |
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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] |
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Friday, 23 February 2001 (10.30-11.30) |
"The Solar Wind and Geomagnetic Storms" by Prof. Y. Kamide, STE LAB, University of Nagoya, Japan |
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1 March 2001 |
"Interplanetary Dust Studies using Large Aperture Radars meteor observations" by Diego Janches, IRF, Kiruna |
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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. |
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15 March 2001 |
"Energized heavy ions measured by Interball -2 satellite" by Sachiko Joko, IRF, Kiruna [Abstract] |
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16 March 2001 |
"Lower Hybrid Cavities and Other Plasma Phenomena in the Subauroral Region" by Solveig Høymork, IRF, Kiruna [Abstract] |
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22 March 2001, 10:00 (10 am) |
"Fine Structures in Auroral Emissions" by Jim LaBelle, Dartmouth College [Abstract] |
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22 March 2000, 13:30 (1.30 pm) |
"Wave Propagation in Inhomogeneous Plasmas" by Hans Pécseli, University of Oslo, Norway [Abstract] |
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5 April 2001 |
Reports from EGS XXVI General Assembly in Nice, France, 25-30 March 2001 |
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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] |
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26 April 2001 |
"Motion and Origin of the Noon Poleward Moving Auroral Arcs" by Alexander Kozlovsky, Oulu University, Finland [Abstract] |
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8 May 2001 |
"Imaging of PSCs in 0-3 dimensions" by Carl-Fredrik Enell, IRF, Kiruna [Abstract] |
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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] |
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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
"The physics of the cusp from an Interball perspective", by Ingrid Sandahl, IRF
"Simulations of Charge-Exchange Processes near Mars", by Mats Holmström, IRF-Kiruna
"Modelling small-scale mountain lee-waves over Kiruna", by Sheila Kirkwood, IRF.
"Energized heavy ions measured by Interball-2 satellite", by Sachiko Joko, IRF. *Joko, S., IRF-K, Sweden,
sachiko.joko@irf.se
"Lower Hybrid Cavities and Other Plasma Phenomena in the Subauroral Region", by Solveig Høymork, IRF.
"Fine Structures in Auroral Emissions", by Jim LaBelle, Dartmouth College.
"Wave Propagation in Inhomogeneous Plasmas", by Hans Pécseli, University of Oslo, Norway
"Direct Magnetosheath Plasma Injections into the Closed Geomagnetic Field Region Observed at Mid- and Low-altitudes", by M. Yamauchi
"Motion and Origin of the Noon Poleward Moving Auroral Arcs", by Alexander Kozlovsky, Oulu University, Finland
Svalbard. The auroral arc motion was monitored at 0800 - 1300 MLT by the
"Imaging of PSCs in 0-3 dimensions" by Carl-Fredrik Enell The method generally used in studies of polar stratospheric clouds is "Inertial Resistivity and Current Limitation in a Collision-free and Inhomogeneous Plasma" by Martin Bohm, Department of Space Physics, Umeå University, Kiruna
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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] |
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11 October 2000 |
Dr. Alya Osepian, PGI Murmansk, "A pulsating regime of whistler cyclotron instability" |
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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] |
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17 October 2000 |
Rickard Lundin, "Planetary Plasma Acceleration Processes: Implications on Astrophysics" [Abstract] |
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26 October 2000 |
Yusuke Ebihara, "Wedge-Like Ion Dispersion in the Inner Magnetosphere: Viking Observation and Particle Simulation" [Abstract] |
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31 October 2000 |
Takayuki Kanda, "A brief introduction to our group in Tohoku University and my background in space physics" [Abstract] |
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7 November 2000 |
Uwe Raffalski, "The SOLVE/Theseo2000 ozone loss campaign in Kiruna during winter1999/2000. Part 1: An overview" [Abstract] |
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9 November 2000 |
Hans Nilsson, "EISCAT and DMSP observations of the quiet time evening sector ionosphere" [Abstract] |
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.
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.
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.
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.
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.
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23 May 2000 |
"My experience as an environmental researcher", by Sachiko Joki |
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9 May 2000 |
Henrik Svensmark, Danish Space Research Institute [Abstract] |
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2 May 2000 |
"What does a single number say about a winter's ozone depletion?" by Johan Arvelius [Abstract] |
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4 April 2000 |
"Some aspects on Incoherent-Scatter Radars" by Micce Hedin [Abstract] |
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28 March 2000 |
"Some notes about past, present and future Ionosondes in Sweden" by Christer Jurén [Abstract] |
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21 March 2000 |
"Why study IRF? A presentation of Science & Technology Studies(STS)" by Marta Nyborg, Linköping University [Abstract] |
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14 March 2000 |
"Global atmospheric electric circuit and geomagnetic substorm interrelation: a possible new link between solar and terrestrial phenomena?" by Evgenia Belova [Abstract] |
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7 March 2000 |
Olle Norberg |
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29 February 2000 |
"Climate forcing by anthropogenic aerosols", by Robert Charlson, USA |
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15 February 2000 |
Winter Cities Conference in central Kiruna |
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8 February 2000 |
Yasuhito |
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1 February 2000 |
Tima Sergienko |
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24 January 2000 |
"The cusp as seen from Interball" by Ingrid Sandahl [Abstract] |
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11 January 2000 |
"Direct plasma acceleration by the radiation?" by M. Yamauchi [Abstract] |
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6 April 2000 |
"Radar Micrometeors studies at Arecibo - an overview" Diego Janches, USA [Abstract] |
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23 March 2000 |
"What is the big difference between biological and technical image processing?" Thomas Lindblad, KTH [Abstract] |
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10 February 2000 |
"Dynamic Trapping of Electrons in Space Plasmas" by Martin Bohm [Abstract] |
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27 January 2000 |
Ingemar Häggström |
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.
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.
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14 December 1999 |
"Ring current proton precipitation and its consequence to the ionosphere" by Yusuke Ebihara [Abstract] |
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25 November 1999 |
" Source and loss processes of magnetospheric plasma" by Bengt Hultqvist |
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23 November 1999 |
"Artificial airglow and analysis of ALIS data" by Björn Gustavsson [Abstract] |
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16 November 1999 |
Seminarium: Origin of Life, Hans Nilsson och Ingrid Sandahl [Abstract] |
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11 November 1999 |
"Meteorskur värdig millennieskiftet?" by Asta-Pellinen-Wannberg [Abstract] |
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9 November 1999 |
"ENA Imaging of Planetary Magnetospheres" by Pontus C:son Brandt [Abstract] |
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.
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.
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.
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.
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.
IRF popular or general seminar
IRF plasma seminar (PS)
IRF atmospheric seminar (AS)
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