A reformulation of lower-hybrid wave propagation and absorption

Abstract

A full wave solution of the propagation and resonant absorption of lower-hybrid waves in an inhomogeneous plasma using the cold plasma model is carried out and compared with results obtained in an infinite homogeneous plasma medium. It is found that the density gradient coupled to finite poloidal model number allows the lower-hybrid wave to reach the hybrid layer for the case of purely perpendicular propagation. Such a wave is evanescent in the infinite homogeneous plasma. The analysis also shows that, for the cold plasma model, roughly equal amounts of energy are absorbed by the ions and electrons in the resonant layer. The analysis may have some bearing on the experimental efforts to propagate lower-hybrid waves into the interior of tokamak plasmas.