Modelling forced electron oscillations in a spatially confined plasma

Summary form only given. The dynamics of modulated electron and ion beams in collisionless plasma is largely determined by collective high-frequency electric fields. In the event of small amplitudes the response of plasma to an external perturbation can be found analytically by linearising the corresponding equations. In the present work through the simulation of a spatially confined plasma with PIC method the non-linear response of plasma to a periodic perturbation of high amplitude is found. The amplitude and phase of the forced oscillations depending on the frequency and amplitude of beam modulation are determined. It is revealed that when exciting oscillations there appears a constant component of the electric field in the system. It is found that in quite a short time (10-20 plasma periods) the oscillatory energy converts into the thermal one because of the non-linearity of the beam-plasma interaction. Electron temperature sharply increases with simultaneous decreasing of the amplitude of the forced oscillations.