Launching conditions for electron cyclotron heating in a sheared magnetic field

摘要

The launching conditions for an electron cyclotron wave in a plasma with a sheared magnetic field are studied. One dimensional second order coupled equations are solved for the ordinary and extraordinary modes. It is shown that, for wave absorption, the rotation angle and ellipticity of the wave should be determined by taking into account the effect of the sheared magnetic field, particularly in heliotron/torsatron configurations. Launching conditions for effective heating are obtained for second harmonic extraordinary mode heating in the Heliotron-E, CHS and LHD helical devices.