Abstract

An advanced kinetic simulation method has been developed and implemented in the HIDENEK code to study large space-scale, low-frequency electromagnetic phenomena occurring in inhomogeneous plasmas. The present method is specially designed for high magnetic field (W_cm W_pm ), inhomogeneous plasma simulations. The guiding-center approximation with magnetic drifts is adopted to the perpendicular motion of the electrons, whereas the inertia effect is retained in their parallel motion. Also, a slightly backward time-decentered scheme is introduced to the equations of motion and the Maxwell equations. These equations are combined to yield the full-implicit, coupled field-particle equations which allow us to determine the future electromagnetic field in a large time step compared to the electron time scales with the diamagnetic drift and magnetization currents being included. As a demonstration of the present simulation method, three physics applications are shown for the electromagnetic beam-plasma instability, the temperature anisotropy-driven Alfven-ion-cyclotron instability, and the external kink instability of the peaked-density current beam. A remarkable pitch-angle scattering of the ions is observed in the first two applications in association with the plasma instabilities. In the third application to an inhomogeneous, finite-beta plasma of the three dimensions, a helical deformation is shown to take place to the initially straight beam and magnetic axis in an ideal magnetohydrodynamic time scale.