Parametric Instabilities of Electron Cyclotron Waves in Plasmas

摘要

We have studied the parametric instabilities of electron cyclotron waves in the Elmo Bumpy Torus (EBT) ring and the large tokamaks eg. PLT. In the EBT, the electron cyclotron pump of finite wavenumber k sub o decays into two Bernstein modes at the second harmonic cyclotron layer and can account for the heating of the ring in the intitial phase. The coupling coefficient for this decay vanishes for a dipole pump, whereas the convective threshold with finite k sub o is about 200 W/sq cm. For large tokamaks, the convective threshold for various decay channels turns out to be about or > 200 KW/sq cm at 3mm wavelength. (Author)