Thermal effects on longitudinal waves instabilities in rotating beam-plasma interaction

Abstract

The thermal effects of charged particles on longitudinal wave instabilities in the interaction of a relativistic rotating electron beam with a magnetized plasma are studied using the standard linearized Vlasov theory. The dispersion relations of longitudinal waves are obtained in two different frequency limits, i.e., when the wave frequency is either much lower or much higher than the electron gyro-frequency. Considering these dispersion relations and finding the growth rates of the instabilities, it is found that for the smaller wave frequency, the instability is not limited to a specific temperature range and the growth rate increases with the beam velocity, while for the larger wave frequency, not only the instability occurs in a specific temperature range, but also the growth rate decreases with the relativistic beam velocity contrary to nonrelativistic beam velocities.