Temperature and density variations in the dusk and dawn plasmasphere as observed by interball tail in 1999 – 2000 Original Research Article

The data on cold ion fluxes measured by the ALPHA 3 instrument on Interball-Tail in July – October 1999 when the spacecraft crossed the dusk side outer plasmasphere, and in January – April 2000 when it crossed the dawn side plasmasphere are analyzed. Correlation of cold ion parameters in the plasmasphere with indices of geomagnetic activity and parameters of the external solar wind flow is examined. In the innermost observed part of the dawn plasmasphere ion temperature is increasing with MLT from post midnight to prenoon. In the outermost plasmasphere no temperature dependence on MLT was observed. It is revealed that cold ion density in the dusk and dawn side outer plasmasphere is increasing with increasing solar wind ram pressure.