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P: Fachverband Plasmaphysik
P 26: Magnetic Confinement II - Helmholtz Graduate School V
P 26.3: Talk
Thursday, March 8, 2018, 14:50–15:15, A 0.112
Microwave beams in plasmas: numerical study of scattering and reflections in the semiclassical limit. — •Lorenzo Guidi1, 2, Omar Maj1, 2, Antti Snicker1, 3, Alf Köhn1, 4, Hannes Weber1, Caroline Lasser2, and Emanuele Poli1 — 1Max-Planck-Institut für Plasmaphysik, D-85748 Garching (DE) — 2Technische Universität München, D-85748 Garching (DE) — 3Institute of Interfacial Process Engineering and Plasma Technology, Univeristy of Stuttgart, D-70569 Stuttgart (DE) — 4Department of Applied Physics, Aalto University, FI-00076 Aalto (FI)
Due to the large use of microwaves in nuclear fusion related experiments, fast and reliable numerical simulations of their behaviour are crucial to both understand present devices (e.g., ASDEX Upgrade) and guide the design of future ones (e.g., ITER). We will show how in the short-wavelength approximation (semiclassical limit) one can build rigorously such for the following two problems:
1. The problem of scattering induced by fluctuations of the plasma density can be formulated by means of the so called wave kinetic equation, whose solution provides the average effect of fluctuations on the beam. We designed a Monte-Carlo scheme for it, and implemented it in a code - WKBeam - which can simulate realistic ITER scenarios.
2. In the framework of reflectometry studies, the asymptotic methods routinely used in the fusion community generally fail to describe the beam in the neighborhood of turning points. We show how we can solve this issue by reconstructing the beam from an opportunely initialized wave packet.