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Hon.-Prof. Sibylle Günter

Photo von Hon.-Prof. Sibylle Günter.
Phone
+49 89 3299 1342
Room
E-Mail
sibylle.guenter@tum.de
Links
Homepage
Page in TUMonline
Group
Max-Planck-Institute for Plasmaphysics (IPP)
Job Title
Honorary Professor at the Physics Department
Consultation Hour
nach Vereinbarung, Termine: christina.hegenberg@ipp.mpg.de

Courses and Dates

Offered Bachelor’s or Master’s Theses Topics

Modellierung relativistischer Elektronen in Tokamak Plasmen
Major tokamak disruptions are one of the major challenges for realizing a tokamak fusion power plant. During such an event, the energy confinement of the plasma gets lost on a short time scale such that the temperature of the plasma drops by orders of magnitude. As a result of the increasing resistivity and the large plasma current, a strong toroidal electric field arises that can accelerate electrons to relativistic velocities. Via collisions, the number of such runaway electrons (REs) can increase exponentially until the whole plasma current is carried by REs. When such an RE beam is eventually lost in a future reactor like ITER, it could lead to massive loads onto material components and deep melting such that avoidance and mitigation is of high priority. Experiments in present devices provide an excellent basis for developing and validating modeling tools that can eventually predict the phenomena in ITER. One of the puzzling observations from the ASDEX Upgrade experiment in Garching is that the formation of a RE beam depends on the value of the edge the field line helicity close to the plasma boundary ("safety factor" q95). Large scale plasma instabilities are likely playing an important role for this threshold. The non-linear magneto-hydrodynamic (MHD) code JOREK (see the code website https://www.jorek.eu) developed by an international community has the necessary ingredients to simulate REs in realistic 3D tokamak geometry and their interaction with plasma instabilities. The aim of this master project is to simulate experimental discharges with and without RE beam formation using a RE fluid model to reveal the origin of the experimentally observed threshold. The work will be conducted within the "MHD and fast particles group" at the Max Planck Institute for Plasma Physics in Garching in close contact with the experiment and our international collaborators.
suitable as
  • Master’s Thesis Nuclear, Particle, and Astrophysics
Supervisor: Sibylle Günter
Nichtlineare MHD-Simulationen zum X-Punkt-Strahler in Tokamaks
One of the most important challenges in magnetic fusion research is the heat exhaust at the plasma edge. Without any additional measures, the heat fluxes at the edge of a fusion power plant would be similar to the heat flux at the surface of our sun. The usual solution for that problem is to modify the magnetic field geometry in such a way that the last closed flux surface (separatrix) leads the heat flux along magnetic field lines into a so-called divertor chamber where high plasma densities and low temperatures ensure high radiation losses, protecting the metallic walls of the device. A quite new development in this respect is to create a zone of high radiation within the last closed flux surface just above the so-called X-point by injecting dedicated impurities into the plasma. These impurities result in strong radiation losses that might cause pressure gradients within a magnetic surface. The latter corresponds to an MHD unstable situation. The task of this master thesis is to model such situations, using our non-linear MHD code JOREK, in order to understand and optimize heat exhaust by X-point radiation.
suitable as
  • Master’s Thesis Nuclear, Particle, and Astrophysics
Supervisor: Sibylle Günter
Simulation vertikaler Plasmainstabilitäten am ASDEX Upgrade Tokamak
Fusion plasmas with a vertically elongated cross section like they are studied in present tokamaks and are foreseen for the large future ITER experiment develop vertical instabilities when the energy confinement of the plasma is lost during the “thermal quench” of a major disruption event. Non-linear magneto-hydrodynamic simulations coupled to resistive wall models describing the conducting structures (such as vaccum vessel and coils) can reproduce experimentally observed phenomena accurately. For ITER, vertical instabilities are a big concern as they can, e.g., lead to large forces onto conducting structures as well as massive heat loads onto plasma facing components. Beyond a threshold of the plasma elongation, the vertical instabilities can normally not be avoided even with active control. There is, however, an experimental observation from ASDEX Upgrade that the plasma may remain vertically stable in spite of significant elongation under specific conditions. Theoretically, such a “neutral point” for the vertical motion is expected, but it is not clear from experiment and theory how robust it would be. In this master project, the described experimental condition will be simulated with the non-linear magneto-hydrodynamic (MHD) code JOREK (see the code website https://www.jorek.eu). The aim is to reproduce the neutral point observation and study the robustness to small variations of the plasma configuration (initial current and pressure profile, initial location, etc.). If possible, concrete proposals for future experiments should be deduced that will allow to validate the findings. The work will be conducted within the "MHD and fast particles group" (very international, English speaking) at the Max Planck Institute for Plasma Physics in Garching in close contact with the experiment and our international collaborators.
suitable as
  • Master’s Thesis Nuclear, Particle, and Astrophysics
Supervisor: Sibylle Günter
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