Full-Wave Studies of Lower Hybrid Wave Propagation in Tokamaks

A full-wave electromagnetic field solver valid the lower hybrid range of frequencies (LHRF) has been developed that utilizes a semi-spectral representation for the RF electric field. Spurious numerical behavior of the field solver that was found to be related to the inclusion of finite electron Larmor radius terms in the wave equation is discussed. The removal of these terms is shown to eliminate all spurious mode generation, leading to well-behaved electric field solutions for parameters typical of LH current drive experiments in present day sized tokamaks.