Sam Frank
MIT
Tuesday, November 19, 2019
5:00pm
n the simulation of lower-hybrid current drive in tokamaks ray-tracing is currently the workhorse simulation tool used to design experiments. However, ray-tracing has yet to be extensively validated against full-wave simulations. Due to recent advancements in computation it is now possible to simulate lower-hybrid wave propagation in medium-sized tokamaks by a direct solve of the wave equation after it has been Fourier analyzed for a single frequency. Simulations such as these are of significant interest since they are capable of simulating weak-damping scenarios in modern tokamaks where current ray-tracing techniques’ assumptions could possibly break down. However, calculations of the non-Maxwellian damping of the lower-hybrid wave requires an iteration between the full-wave solver and a 3D Fokker-Planck solver in order to self-consistently model the wave fields. Techniques for iteration between the TORLH full wave and the CQL3D Fokker Planck codes by coupling the two codes with a quasi-linear RF diffusion coefficient will be shown and the results of these iterations and their implications for lower-hybrid current drive theory will be discussed.
Plasma Science and Fusion Center
Massachusetts Institute of Technology
77 Massachusetts Avenue, NW17
Cambridge, MA 02139
info@psfc.mit.edu
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