Thermal Ion Outflows At Nightside Polar Cap Measured By Hyperboloid Instrument On Interball-2 Altitudes

Abstract

An analysis of the ionospheric ion outflow at nightside of the polar cap measured on INTERBALL-2 by the HYPERBOLOID low energy mass-angle spectrometer is presented. Detailed analysis of simultaneous measurements of higher energy electron and ion intensities was performed to choose the ion flow driven only by thermal en- ergy ionospheric plasma. The cleft ion fountain was excluded from observations. The data of the SpureT polar wind and other outflow types founded at chosen time are & cedil;presented. Data was selected for wibnter and summer period for northern hemisphere. Thus the outflow when ionosphere was absolutely dark or sunlight was studied. From the thermal ions measurements six types of outflows were found in the polar cap. Four from them are polar wind outflow and two other are due to addition heating sources. The dependence Summer-Winter was found. Strong dependence of O+ outflow from polar rain intensities was found.