Excitation of waves at 2 ω_p,e and back propagating waves at ω_p,e: a parametric study

Abstract. We present a parametric study of electrostatic waves generated with angular frequencies 2 w_p,e and - w_p,e by an electron beam using a one-dimensional Vlasov code. We consider a background plasma consisting of three components: two electron populations (a background and a beam) and a proton population (with a mass ratio m_p /m_e = 400 and temperatures T_p = T_e = T ). We investigate the influence of different beam parameters on the nonlinear growth rate of waves with angular frequency 2w_p,e and compare the results of the numerical experiments to theoretical predictions. We also examine the presence and excitation of back propagating waves with angular frequency w_p,e. A discussion on the possible generating mechanisms of the different modes observed in these simulations is also presented.