Cyclotron harmonic wave propagation and instabilities: II. Oblique propagation

Abstract

Part I of this paper has discussed longitudinal wave propagation, perpendicular to the static magnetic field, in a warm homogeneous magnetoplasma. Part II extends the work to oblique propagation. The ring and Maxwellian transverse velocity distributions, which are absolutely unstable and stable, respectively, for perpendicular propagation, are shown here to be both absolutely unstable for oblique propagation. Their instabilities are radically affected by the introduction of axial velocity spread. A detailed study is made for the cases of a Maxwellian transverse distribution with resonance and resonance-squared axial velocity distributions. It is shown that abolute instabilities occur at high energy anisotropies. These become convectively unstable as teh anistropy is reduced, and are quenched as isotropy is approached. The isotropic Maxwellian is treated in detail, and shows both cyclotron and Landau collisionless damping.