Power Conserving Lower Hybrid Current Drive Simulations with TORLH/CQL3D

First Speaker: Sam Frank


Tuesday, December 1, 2020



PSFC Student Seminars

Lower Hybrid Current Drive (LHCD) is a high efficiency plasma current drive actuator with a number of properties that make it attractive for high-field tokamak reactors. However, propagation and absorption of LH waves is still not well understood or able to be modeled predictively in most cases, and typical raytracing/Fokker-Planck simulations fail to replicate experimental results. Here, LHCD is modeled with a higher-fidelity full-wave/Fokker-Planck approach in which the electric field is solved for directly. This approach, unlike raytracing, properly handles interference and reflections making it well suited to model the weakly damped LHCD scenarios found in modern experiments. A key feature of this work is, unlike previous attempts at full-wave simulation of LHCD, the TORLH/CQL3D iteration used has a high degree of self-consistency and conserves power to higher accuracy than previous work. The steps taken to achieve this high degree of power conservation will be discussed and early results of power conserving simulations indicating differences in the structure of the driven plasma distribution will be examined.