Master thesis project for students at KTH
http://www.nada.kth.se/~jaun/Projects.html
NADA & Alfvén Laboratory, Royal Institute of Technology, Stockholm, Sweden

Gyrokinetic modeling of macro-instabilities in an RFP

Toroidal reversed magnetic field pinch (RFP) configurations are conceptually very attractive for the confinement of fusion plasmas because of the efficient use they make of the plasma current: not only does it generate a large fraction of the confining magnetic field necessary to isolate the plasma from the outside world, but the current also contributes directly to the plasma heating through Ohmic dissipation. Experiments such as the EXTRAP-T2 in Stockholm unfortunately show that low frequency instabilities appear and destroy the confinement. The Ohmic power is then rapidly lost to the vacuum vessel and the plasma remains at a relatively low temperature.

A partial understanding of pressure driven instabilities, their saturation and the transport induced has already been obtained using simple magneto-hydrodynamic (MHD) models, which assimilate the plasma with a resistive fluid. The finite frequency comparable with the species drift frequency, the finite Larmor radius and the plasma rotation have however been neglected so far, even if these are all expected to affect the global RFP stability and could provide an explanation for the anomalous ion temperatures measured in the plasma core.

To start this numerical modeling project, a recent version of the cylindrical ISMENE-V code [1] will be adapted and tested for the RFP geometry using both cold-fluid and gyrokinetic plasma models. Parametric studies will then be carried out using the numerical tool to determine potential new stability windows and to confront the numerical results with the experimental measurements.

This is a challenging project for a computational physics student willing to explore what is today an unknow parameter space.

  1. K. Appert, T. Hellsten, J. Vaclavik, L. Villard, Comput. Phys. Comm. Vol 40 (1986) 73
For further information, contact André JAUN and consult http://www.nada.kth.se/~jaun.