ENHANCED ELECTRON CYCLOTRON EMISSION DURING LOWER HYBRID WAVE DRIVE

High frequency electromagnetic radiation driven by lower hybrid wave is studiedbased on three wave (the hybrid wave, high frequency electrostatic wave and electromagnetic wave) resonant interaction. The guiding center formalism of Vlasov equation is followed to obtain the nonlinear coupling coefficients including kinetic effects. Velocity space integrals in the coupling coefficients are strictly performed in small k z  approximation. General nonlinear dispersion relations of the parametric instability are obtained. Analytical analysis indicates that: (1) due to kinetic coupling effects, lower hybrid wave can excite electron Bernstein wave accompanied by high frequency electromagnetic wave; (2) the elctromagnectic radiation driven in this manner is thermal electron cyclotron radiation, and the intensity of the radiation is enhanced when increasing the plasma temperature and density. It is consistent with most experimental observations. This suggests that the present instability can be responsible for the enhanced electron cyclotron emission during lower hybrid wave drive and be regarded as the origin of the electron cyclotron emission in the plasma.