Progress in the kinetic theory of electrostatic harmonics of plasma waves

Abstract

This paper performs numerical analysis to verify the theoretical predictions of Yoon [“Effects of spontaneous fluctuations in the generalized weak turbulence theory,” Phys. PlasmasPHPAEN 12, 042306 (2005)], according to which the higher harmonics of the electron plasma frequency, generated during the course of electron beam-plasma interaction start to grow initially with fast quasilinear growth rate, which is roughly n times higher than the fundamental Langmuir mode growth rate, n being the harmonic number, but the rapid initial growth soon slows down to the level of fundamental mode growth rate. It is also shown that when the initial wave levels for the harmonics are relatively high, then the overall dynamics is largely dictated by the slow nonlinear growth rate, but when the initial wave levels associated with the harmonic components are artificially suppressed, then the fast quasilinear growth stage is prolonged.