Multi‐Point Observations of the Geospace Plume

Abstract

Simultaneous multi‐instrument observations of the redistribution of cold (<2 eV) plasma of ionospheric origin emphasize the role and importance of this system‐wide phenomenon in the processes and across the regions of geospace. The geospace plume couples the ionosphere, plasmasphere, and magnetosphere from sub‐auroral regions to the magnetopause, on polar field lines and into the magnetotail. We investigate the geospace plume using ground‐ and space‐based observations of the 17 March 2015 major magnetic storm. Strong electric fields, plasma waves, and accelerated heavy ions characterized Van Allen Probes observations at the source of the geospace plume in the dusk sector where energetic ring current ions overlap the outer plasmasphere. On the dayside, Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft sampled the outflowing geospace plume and its involvement in reconnection at the magnetopause. Plume ions were accelerated and subsequently observed at up to ~1‐keV energies in the reconnection exhaust jets.