Effects of electron temperature and electron flow on O-X conversion

Effects of electron temperature and electron flow on Ordinary-Extraordinary (O-X) conversion in the range of electron cyclotron frequency are investigated. The modified optimal parallel refraction index, Nzc, and the conversion coefficient are obtained analytically from the kinetic dispersion relation. The presence of finite electron temperature shifts the O-X conversion layer towards a region of lower density and increases the value of Nzc; while the effect of electron flow depends on its direction with respect to the parallel wave vector. When the electron flow is along the parallel wave vector, Nzc will be increased and the effects of finite electron temperature and finite electron flow accumulate. As a result, a more oblique incidence angle is required for efficient O-X conversion. For typical Tokamak plasmas, the efficiency of O-X conversion will decrease without the consideration of the two effects. When the electron flow is in the direction opposite to the parallel wave vector, the two effects compete, even cancel each other