Statistical analysis of fast dawnward and duskward ion flows in the near and mid-distant magnetotail observed by GEOTAIL Original Research Article

We obtained the occurrence rates and characteristics of fast dawnward and duskward ion flows whose speed exceeded 400 km/s and which are observed in the near and mid-distant magnetotail by analyzing data of plasma, magnetic field and electric field obtained by the GEOTAIL spacecraft. In both dawnward and duskward flows, the ion density was low, the ion temperature was high, and the ion pressure was low compared to those in a nominal state. Such fast dawnward ion flows are possibly due to E × B drifts with the electric fields directed to the center of magnetic field line curvature.