The solar wind plasma density control of night-time auroral particle precipitation

Abstract

DMSP F6 and F7 spacecraft observations of the average electron and ion energy, and energy fluxes in different night-time precipitation regions for the whole of 1986 were used to examine the precipitation features associated with solar wind density changes. It was found that during magnetic quietness (/AL/<100 nT), the enhancement of average ion fluxes was observed at least two times, along with the solar wind plasma density increase front 2 to 24 cm-3. More pronounced was the ion flux enhancement that occurred in the b2i-b4s and b4s-b5 regions, which are approximately corresponding to the statistical auroral oval and map to the magnetospheric plasma sheet tailward of the isotropy boundary. The average ion energy decrease of about 2-4 kev was registered simultaneously with this ion flux enhancement. The results verify the occurrence of effective penetration of the solar wind plasma into the magnetospheric tail plasma sheet. © European Geosciences Union 2004.