Master theses projects & shorter student projects
Below are topics available for Master’s thesis projects and shorter student projects at the Swedish Institute of Space Physics (IRF).
High fluxes of suprathermal electrons in the Earth magnetotail
Study the source regions of high energy suprathermal electrons in the Earth magnetotail using ESA Cluster satellite observations during 12 years of its mission.
Background
Cluster consists of 4 spacecraft with orbit apogee at 19 Earth radii. Since 2001 Cluster has collected large database of Earth magnetotail observations under different conditions (different phases of solar cycle, different solar wind conditions, different stages of reconnection, etc.).
This allows to address statistically many important science topics where previously mainly event based studies have been carried out. Cluster spacecraft allow the most detailed 3D in situ observations of plasma that are accessible experimentally and the obtained knowledge can be of importance not only understanding Earth magnetosphere but even understanding such physically very distant phenomena as solar flares.
Project
One topic of very high importance is the suprathermal (energies manyfold larger than thermal energies) electron acceleration in the Earth magnetotail. For example, much of our knowledge on distance solar flares, is based on X-ray emissions generated by similar suprathermal electrons in the Suns corona.
The suprathermal electrons can be observed in situ in the Earth magnetotail and are believed to be created due to magnetic reconnection and associated physical processes. There have been detailed event studies of such suprathermal electron acceleration within magnetic islands of tail current sheet during magnetic reconnection, or magnetic flux pile up regions created due to reconnection jets.
Numerical simulations have suggested different possible acceleration mechanisms. However, statistically it has not been resolved what is the most efficient mechanism generating these electrons in the Earth magnetotail.
The large database of Cluster would allow to address this question. The goal of the project would be to identify all Cluster events where suprathermal electrons show localized high fluxes, thus suggesting that Cluster is passing through the electron generation region, and classify these regions based on the properties of the magnetic field and plasma. For example, are these regions in the center of current sheet, at the front of magnetic pile up regions, within magnetic islands etc.
Plan
| Week | Task |
|---|---|
| 1 | Basic understanding of Eart magnetosphere and magnetotail |
| 2 | Basic understanding of Cluster, Cluster instrument and Cluster Active Archive |
| 3 | Test routines of analyzing large databases of Cluster data |
| 4-5 | First test runs of analyzing some events with high suprathermal electron fluxes |
| 6-7 | First test runs of generating event database |
| 8-9 | Critical review of first results, initial classification attempt |
| 10 | Start report writing |
| 11-13 | Regeneration of the final event databse for the project |
| 14-16 | Classification and typical example deeper analysis |
| 17-18 | Report writing |
| 19 | Reserve |
| 20 | Report presentation |
Contact person: Yuri Khotyintsev, yuri@irfu.se
Timing analysis using multi-spacecraft data
To develop a better method to estimate velocities using multi-spacecraft data and apply it study the distribution of scales and orientations of current sheets for the current sheets observed in the Earth’s magnetosheath.
Background
Estimating scales and speeds of plasma structures is crucial for understanding of many plasma phenomena. One such plasma structure are the current sheets forming in different parts of the magnetosphere as magnetotail, magnetopause, turbulent magnetosheath and knowledge of their scale, speed and orientation from observations is important for comparisons with theories of magnetic reconnection and plasma turbulence. For true quantitative comparisons one needs to have full control of the uncertainties.
Based on data from one spacecraft, it is generally not possible decide whether an observed variation is coming from temporal or spatial changes. To resolve this ambiguity, ESA launched a multi-spacecraft Cluster mission, which consists of 4 spacecraft flying in a constellation with orbit apogee at 19 Earth radii. So, if 4 spacecraft (located in corners of a tetrahedron) observe the same plasma structure, we can assume the structure is planar and moving at a constant speed and it straightforward to compute the velocity of the structure. But what if the observed profiles are similar and not identical? How can we quantify the error?
Project
In this project we will extend the existing methods for timing analysis of multi-spacecraft to provide quantitative estimates of the error for the both the magnitude and direction of the velocity vector.
We will test the method on surrogate data wich can simulate background noise and accelerated motion of current sheets, but also on several cases of real current sheet observed by Cluster.
As the last part of the project we will apply the method to a large number of small-scale current sheets observed in magnetosheath.
The method developed will have important implication for analysis of multi-spacecraft data from the Cluster mission as well as from the future NASA MMS mission.
Plan
| Week | Task |
|---|---|
| 1 | Basic understanding of Eart magnetosphere and magnetotail |
| 2 | Basic understanding of Cluster, Cluster instrument and Cluster Active Archive |
| 3 | Test routines of multi-spacecraft timing analysis of Cluster data |
| 4-5 | Define ways to improve the timing estimates |
| 6-7 | Generate surrogate data and test the improvements on it |
| 8-9 | Critical review of first results |
| 10 | Start report writing |
| 11-13 | Update the method and retest |
| 14-16 | Apply the method to magnetosheath current sheets |
| 17-18 | Report writing |
| 19 | Reserve |
| 20 | Report presentation |
Contact person: Yuri Khotyintsev, yuri@irfu.se
Ion drift meter instrument design & prototype development
The ion drift meter is a space instrument that measures the 3-D ion drift velocity in the ionosphere. The working principle is straightforward: The ion currents coming through an aperture will be measured by multiply-segmented planer electrodes, the ratios of which provide the impinging direction of the bulk ion. With the help of spacecraft/rocket orbital motion, we can derive the ion bulk velocity.
The bulk ion drift velocity is a key parameter for understanding the ionosphere–thermosphere coupling in the upper atmosphere, where the momentum exchange between space and the atmosphere occurs.
The IRF/SSPT group will design, develop and implement IDM instruments for possible future missions, including terrestrial rocket missions and low-altitude spacecraft.
In addition to the Earth-based measurements, we aim to deploy Earth-like planetary ionospheres (e.g., Mars and Venus), outer planetary system, and interplanetary/interstellar probes. In this project, we will design an IDM instrument and develop a prototype.
The prototype will be tested and verified in a vacuum chamber. We also aim to operate the prototype in the real environment, possibly with a rocket experiment or small satellite (e.g., CubeSat).
The project includes a part of the following tasks:
- Theoretical performance assessment
- Performance analysis by computer simulation (possibly with GPU programming)
- Mechanical design
- Electrical design (incl. power system, frontend electronics, analog processing, etc.)
- Testing and verification in the lab
Contact persons:
Yoshifumi Futaana, futaana@irf.se
Manabu Shimoyama, manabu@irf.se
Stas Barabash, stas@irf.se
Published in May 2022
Electric Potential at Comet 67P
The Rosetta mission to comet 67P has enabled us to study the interaction of the solar wind with the plasma environment of a comet over an extended period of time, and therefore a vast range of parameters. IRF Kiruna contributed to the scientific payload of this mission with the mass-resolving ion spectrometer ICA that measures the velocity distribution of ions close to the comet nucleus.
This solar wind – cometary plasma interaction is observed as deflection and gradual deceleration at low cometary activity, and evolves into a fully developed bow shock at high activity comets. The electric potential of the upstream solar wind differs from the electric potential deep within this interaction region. Nilsson et al. (2022) reconstruct the upstream solar wind speed from measurements close to the nucleus, and also provide an estimate for the potential difference between the upstream solar wind and the observation point.
In this study we will use this dataset to explore the generation mechanisms of the electric potential around the comet. Potential driving factors include the heliocentric distance and outgassing rate, as well as solar wind conditions. Additionally, we will also investigate the spatial distribution of the electric potential near the comet nucleus.
Project tasks:
- Familiarisation with the methods and tools of scientific data analysis.
- Analysing the dataset for correlation with different orbit parameters, such as heliocentric distance (using Python/NumPy).
- Analysing the dataset for correlation with different plasma parameters measured by ICA and other instruments, such as outgassing rate (using Python/NumPy).
- Visualising the results for reports, and potentially scientific publication (using Python/Matplotlib).
Literature:
Nilsson, H., Moeslinger, A., Williamson, H. N., Bergman, S., Gunell, H., Wieser, G. S., et al. (2022). Upstream solar wind speed at comet 67p: Reconstruction method, model comparison, and results. Astronomy and Astrophysics, 659, A18. https://doi.org/10.1051/0004-6361/202142867
Contact persons:
Anja Möslinger, anja.moeslinger@irf.se
Yoshifumi Futaana, futaana@irf.se
Hans Nilsson, hans.nilsson@irf.se
Simulation of scattering characteristics of Polar Stratospheric Clouds
Simulating lidar signals is important for various kind of sensitivity studies In order to simulate realistic signals from PSCs scattering characteristics for various types of PSCs are required.
It is possible to calculate such characteristics based on measured size distributions and assumptions about particle shape.
Tasks:
- Find information about measured size distributions and particle shapes from available literature.
- Implement a loop over a given size distribution in an available programme to calculate Mueller matrix and phase function for a single particle using the T-matrix approach.
- Calculate scattering characteristics for various size distributions and particle shape approximations.
- Evaluate the sensitivity of scattering characteristics to various parameters of the size distribution.
Prerequisites:
- Basic knowledge of a programming language; the code will be mostly in Fortran.
- Some knowledge of physical processes in the atmosphere.
Contact person: Peter Voelger, peter.voelger@irf.se
Published in March 2020