EXCITATION OF LARGE-AMPLITUDE ALFVEN WAVES IN A NONRELATIVISTIC ELECTRON-POSITRON PLASMA WITH A TEMPERATURE ANISOTROPY T-PERPENDICULAR-TO-GREATER-THAN-T-PARALLEL-TO

Excitation of large-amplitude Alven waves in an anisotropic electron-p ositron plasma is investigated with a two-and-one-half-dimensional (2- 1/2-D), electromagnetic particle code. If the plasma distribution is a bi-Maxwellian with T-perpendicular to/T-parallel to > 1, where the su bscript symbols denote directions perpendicular and parallel to the am bient magnetic field, Alfven waves with arbitrary polarization are gen erated. Simulations show that the amplitude of the waves increases bot h with increasing temperature anisotropy and parallel plasma beta(para llel to). The stabilization of individual wave modes occurs sequential ly, from higher values of wave number down to lower ones,in the evolut ion of the temperature anisotropy instability. Wave-particle scatterin g by the enhanced waves maintains the initially bi-Maxwellian characte r throughout the simulation, even as it reduces T-perpendicular to and increases T-parallel to. After saturation of wave magnetic energy a l arge residual temperature anisotropy still remains and persists throug h the end of the simulation. (C) 1997 American Institute of Physics.