THE EFFECT OF WAVE-PARTICLE INTERACTIONS ON THE POLAR WIND - PRELIMINARY-RESULTS

A Monte Carlo simulation was developed in order to study the effects o f wave-particle interactions (WPI) on the plasma outflow in the polar wind. The simulation also considered the other mechanisms included in the 'classical' polar wind studies such as gravity, the polarization e lectrostatic field, and the divergence of geomagnetic field lines. Alt hough the plasma consisted of electrons, H+ and O+ ions, we emphasized the behavior of H+ in this preliminary study. The ion distribution fu nction, as well as the profiles of its moments (density, drift velocit y, temperatures, etc.) were found for different levels of WPI, that is , for different values of normalized diffusion rates in the velocity s pace ($) over tilde D-perpendicular to(H+)). We found that as the WPI strength increases: (1) the ion drift velocity increases and its densi ty decreases; (2) the perpendicular temperature T-perpendicular to(H+) increases; (3) the parallel temperature T-parallel to(H+) first decre ases and then increases due to the balance between the parallel adiaba tic cooling and the transfer of the energy from the perpendicular to t he parallel direction; and (4) the temperature anisotropy (T-parallel to(H+)/T-perpendicular to(H+)) is reduced and even reversed in some ca ses. For strong WPI (($) over tilde D-perpendicular to(H+) >> 1), the ion distribution function shows weak conic features at high altitudes.