Max-Planck-Institute for Plasmaphysics (IPP)

Course with Participations of Group Members

Offers for Theses in the Group

Consistent initialization of supra-thermal particles to simulate the interaction with instabilities in magnetically confinement fusion plasmas

Certain processes in magnetic confinement fusion devices require a kinetic treatment of the plasma, while others can be described in a simpler fluid picture. Hybrid fluid-kinetic models are often used, where particle species are described differently. For instance, the interaction of energetic particles (EPs), such as the ones born directly by the fusion processes, with the plasma background is often treated in such a hybrid way. For very non-linear processes, the full distribution function of the kinetic particles needs to be modeled with “markers”, called a full-f model. Since particles are not exactly following the magnetic flux surfaces, a “naive” initialization of markers can lead to a strong unrealistic relaxation of the distribution function when such a full-f description is used [1] causing an artificially reduced growth rate for EP driven instabilities. It is therefore important to construct the marker distribution in the constant of motion space (e.g. like described in [2,3]). In this project, the energetic particle model of the non-linear MHD code JOREK [4,1] will be enhanced to avoid such spurious relaxation effects. First, an existing case, in which particles are not loaded based on their conserved quantities, will be studied to investigate the relaxation of the initial distribution function. Also linear properties of the unstable mode driven by this relaxed EP distribution will be studied. Next, a method previously developed for the initialization of thermal particles will be adapted for the initialization of EPs based on conserved quantities. The method will be extended where needed and then be applied to the previously tested case to demonstrate that the particle distribution does not relax any more. The linear growth rate of EP driven instabilities will be benchmarked against literature and compared to the previous results with relaxation. [1] Bogaarts T.J., Hoelzl M., Huijsmans G.T.A., Wang X., JOREK Team. Physics of Plasmas 29, 122501 (2022). [2] Angelino P, et al, Physics of Plasmas 13, 052304 (2006) [3] Lu Z., et al 2022 https://arxiv.org/abs/2210.04354 [4] Hoelzl M., Huijsmans G.T.A., Pamela S.J.P., Becoulet M., Nardon E., Artol

suitable as

• Bachelor’s Thesis Physics

Supervisor: Sibylle Günter

Current and Finished Theses in the Group