VARIATIONAL DESCRIPTION OF LOWER HYBRID WAVE-PROPAGATION AND ABSORPTION IN FUSION PLASMAS

A variational approach to a global solution of the lower hybrid wave propagation and absorption in fusion plasmas is presented. It is restricted to current drive or electron heating applications (i.e. when no lower hybrid resonance exists) and is based on the use of trial functions which are locally solutions of the homogeneous problem ('eikonal trial functions'). Results in circular cylindrical geometry are presented for which radial power deposition profiles have been calculated. The influence of the main plasma and wave parameters has been investigated, focusing on the effect of the toroidal wave number on the power deposition and also on the wave accessibility and the 'whisperinggallery' phenomena. The radial extension and shape of the power deposition near the reflection layer of inaccessible waves (caustics) are displayed. © 1990 IOP Publishing Ltd.