Accessibility and Energy Depositon of Lower-Hybrid Waves in a Tokamak with Density Fluctuations

Abstract

A wave kinetic equation, including electromagnetic effects, to study the effects of scattering by density fluctuations on the accessibility of lower hybrid waves is derived. A Monte Carlo solution of the wave kinetic equation shows that the scattering, combined with toroidal effects and magnetic shear, can cause large upshifts in $k_{\parallel }$, thus allowing inaccessible waves to penetrate to the plasma center and heat. The implications of these results for past and future lower-hybrid-heating experiments are discussed.