FULL-WAVE THEORY OF A QUASI-OPTICAL LAUNCHING SYSTEM FOR LOWER-HYBRIDWAVES - THE STEP DENSITY CASE

Numerical studies on the use of a quasi-optical grill to couple lower hybrid waves to a plasma, for current drive in tokamaks, are currently under way. Study of the coupling has been carried out in a rigorous w ay, through the solution of scattering from cylinders with parallel ax es in the presence of a plane of discontinuity for electromagnetic con stants. Here we restrict our attention to the case of a plasma with a step density profile and report some results on launched spectra, coup led power and directivity.