Studies on Polar Wind & Its Dependence on Plasma Temperature Using Alouette-II Data

Abstract

The electron density profiles obtained by Alouette-II topside sounder satellite have been used to derive the <i>light </i>ion efflux at high latitudes by solving the continuity and ion momentum equations with the aid of a computer programme. Essentially the departure of the derived H⁺ profiles from the ones expected on the basis of diffusive equilibrium is attributed to the velocity term of H⁺ ions. The dependence of this light ion flux on plasma temperature at an altitude of 1000 km as well as on plasma temperature gradient above 1000 km is studied. It was found that temperature and temperature gradient affect the flux as expected on theoretical basis. The important result obtained is that the light ion efflux mayor may not attain supersonic speed depending upon the plasma temperature and temperature gradient. A low plasma temperature at 1000 km and a higher temperature gradient above 1000 km seem to favour the supersonic flow of light ions at high latitudes.