The Evolution of the Plasma Sheet Ion Composition: Storms and Recoveries

TitleThe Evolution of the Plasma Sheet Ion Composition: Storms and Recoveries
Publication TypeJournal Article
Year of Publication2017
AuthorsDenton, MH, Thomsen, MF, Reeves, GD, Larsen, BA, Henderson, MG, Jordanova, VK, Fernandes, PA, Friedel, RHW, Skoug, RM, Funsten, HO, MacDonald, EA, Spence, HA
JournalJournal of Geophysical Research: Space Physics
Date Published10/2017
Keywordsplasma sheet; Van Allen Probes
AbstractThe ion plasma sheet (~few hundred eV to ~few 10s keV) is usually dominated by H+ ions. Here, changes in ion composition within the plasma sheet are explored both during individual events, and statistically during 54 calm-to-storm events and during 21 active-to-calm events. Ion composition data from the HOPE (Helium, Oxygen, Proton, Electron) instruments onboard Van Allen Probes satellites provide exceptional spatial and temporal resolution of the H+, O+, and He+ ion fluxes in the plasma sheet. H+ shown to be the dominant ion in the plasma sheet in the calm-to-storm transition. However, the energy-flux of each ion changes in a quasi-linear manner during extended calm intervals. Heavy ions (O+ and He+) become increasingly important during such periods as charge-exchange reactions result in faster loss for H+ than for O+ or He+. Results confirm previous investigations showing that the ion composition of the plasma sheet can be largely understood (and predicted) during calm intervals from knowledge of: (a) the composition of previously injected plasma at the onset of calm conditions, and (b) use of simple drift-physics models combined with calculations of charge-exchange losses.
Short TitleJ. Geophys. Res. Space Physics

Page Last Modified: October 24, 2017