EFFECTS OF WAVE-PARTICLE INTERACTIONS ON H-LATITUDE - A COMPARATIVE-STUDY( AND O+ OUTFLOW AT HIGH)

A Monte Carlo simulation was used to study the effects of wave-particl e interactions (WPI) on ion outflow at high latitudes (the auroral reg ion and the polar cap). As the ions drift upward along the geomagnetic field lines, they interact with the electromagnetic turbulence and, c onsequently, get heated in the direction perpendicular to the geomagne tic field. The mirror force converts some of the gained ion energy in the perpendicular direction into parallel kinetic energy. These effect s combine to form an ion-conic distribution. Previous studies of WPI i n the auroral region neglected the body forces (i.e., gravitational an d polarization electrostatic) and the altitude dependence of the spect ral density. In contrast, this work includes the effect of body forces and an altitude-dependent spectral density. The ion distribution func tion, the profiles of ion density, drift velocity, and parallel and pe rpendicular temperatures are presented for both H+ and O+ ions. These results are compared with the ones corresponding to polar wind conditi ons. The main conclusions are as follows: (I) the effect of body force s is more important in the polar wind case and for the O+ ions than it is for the auroral region and the H+ ions, respectively; (2) the O+ i ons are preferentially energized in both regions; (3) both ions (H+ an d O+) are more energetic in the aurural region at most altitudes; and (4) the results of the Monte Carlo simulations agree with the ''analyt ical'' results of the mean particle theory.