Electron beam formation by small-scale oblique inertial Alfvén waves

Abstract

Particle-in-cell simulations reveal characteristics of small-scale nearly perpendicular nonlinear inertial Alfvén waves in the electrostatic limit, during wave steepening and electron beam generation. These electrostatic inertial Alfvén waves (ESIAW) propagate with only weak electron Landau damping for Ti/Te ≫ 1. Nonlinear amplitude initial conditions convectively steepen and evolve higher wavenumber structures similar in morphology and magnitude to previous, results from a fluid-kinetic model. Shorter wavelength acoustic waves emergent during steepened ESIAW wave evolution are found to be instrumental in exciting cold electron beams possessing kinetic energies a few hundred times that of the thermal electron population. This mechanism is one possible explanation for suprathermal electron bursts observed in and near auroral inverted-V events. Copyright 1999 by the American Geophysical Union.