Simulation of dynamics and interactions of charged particles with two electrostatic waves

Summary form only given, as follows. A model is proposed for the nonlinear plasma maser effect, or turbulent bremsstrahlung, in the nonlinear interaction of plasma particles and waves. The model consists of a system of many noninteracting particles interacting with two monochromatic waves. The interactions act as energy and momentum sources and sinks for the particles, analogous to that in a weakly turbulent plasma. The amplitudes and frequencies of the waves determine the dynamics and distribution of the particles. The resulting asymptotic velocity distributions agree qualitatively with existing turbulence theories. It is also found that the second wave, which simulates the effect of the nonresonant wave-particle interaction, can significantly affect the particle dynamics and destroy correlations in their interactions with the first wave. The proposed model simulates the effect of the plasma maser, or turbulent bremsstrahlung, in a weakly turbulent plasma. The origin of the latter effect is the interaction of the nonresonant particles with the resonant and nonresonant waves. The contribution of the nonresonant particles, usually ignored in the standard quasilinear treatment, turns out to be crucial for global energy and momentum conservation, and can affect the overall evolution of the system. Here, resonant waves are waves satisfying the Cherenkov wave-particle resonance condition while the nonresonant waves are those for which neither linear nor nonlinear wave-particle resonance occurs. An example of processes in winch both resonant and nonresonant waves participate is the interaction of plasma particles with the (resonant) low-frequency ion-acoustic waves and the (nonresonant) high-frequency Langmuir waves.