Numerical simulation of the weak beam-plasma interaction

Abstract

The Cerenkov interaction of a weak electron beam with a plasma is studied numerically. Three parts of the nonlinear evolution of the convective instability are discussed. In the first part the understanding of the saturation amplitude of the initial wave and its harmonics is extended. In the second part it is shown that a quasi-linear-like cascade process is responsible for the simutaneous appearance of beam particles and waves which move slower than the original beam velocity. These modes destroy the trapped particle oscillations of the initial wave. The third part of the instability is the development of fast waves whose phase velocities are greater than the original velocity of the beam. It is shown that these waves arise due to a mode coupling mechanism.

Progress in the kinetic theory of electrostatic harmonics of plasma waves

“…Plasmas 12, 052313 ͑2005͒ noise determined by the thermal motions of the particles. Indeed, available Vlasov simulations in the literature 7,20,21,23,29 all seem to report growths of the harmonic modes which are in agreement with Fig. 6, while particle simulations to feature wave amplification property similar to that shown in Fig.…”

“…Its theoretical understanding is, however, still less than complete. 7,20,21,23,28,29 Typical phase-space plot generated by simulations shows that the coherent phase-space vortices which characterize strong beam-plasma interaction do not entirely dissipate in the course of the beam-plasma interaction process, 7,23 which implies that one cannot completely ignore coherent nonlinear effects. 2,[4][5][6][7][8] There is, however, an alternative way to interpret the same phenomenon in terms of coherent nonlinear process.…”

Harmonic Langmuir waves. II. Turbulence spectrum

“…The induced scattering process for the ion-sound modes involves the ions and two S-mode waves, which is a very slow process compared with the time scale of interest to us in the present discussion. Since the late 1960s, it has been shown both in beam-plasma experiments [2][3][4][5]8,[35][36][37] and in numerical simulations, [9][10][11][12][13][14]38 that harmonic waves start to grow while the system is still in the quasilinear growth phase of the fundamental mode. A preliminary version of the kinetic equation for L 2 mode was also derived in Ref.…”

Harmonics of electromagnetic and electrostatic plasma waves

“…5,[18][19][20][21][22][23][24][25][26][27] However, the evidence for transverse harmonic mode is much more rare. 5,[18][19][20][21][22][23][24][25][26][27] However, the evidence for transverse harmonic mode is much more rare.…”