Two dimensional simulation of ion beam-plasm interaction

Abstract

Hybrid plasma simulation is a model in which different components of the plasma are treated differently. In this work the ions are treated as particles while the electrons are treated as a neutralizing background fluid through which electric signals may propagate. Deuterium ion beams incident on the tritium plasma interact with the plasma through the wake electric and magnetic fields of the beam currents. The model is described by the Vlasov-Maxwell-fluid equations with displacement currents omitted in the Ampere's equation. Euler scheme advances the ion positions and velocities while finite difference scheme approximates the spatial derivatives of field quantities. Bilinear interpolation is used in interpolating field quantities from the grid points to push particles in their respective positions. The beam parameters that determine the response of the plasma are the beam velocity V_b, the density n_b and the radius r_b. It was found that the sharpness of the characteristic frequencies for power absorption increased with increasing beam density while increasing the beam radius destroyed the characteristic frequencies and spread the frequency band of the continuous lines. The Joule heating of the plasma fluctuated in time and could be localized. Increasing nb delocalized the heating. The magnetic field profile did not respond sharply to beam parameters but the respond was sufficient enough to cause inhomogeneity in the direction of applied magnetic field Bσ.

Journal of the Nigerian Association of Mathematical Physics Vol. 9 2005: pp. 561-572