Temperature Dependence of Plasmaspheric Ion Composition

TitleTemperature Dependence of Plasmaspheric Ion Composition
Publication TypeJournal Article
Year of Publication2019
AuthorsGoldstein, J, Gallagher, D, Craven, PD, Comfort, RH, Genestreti, KJ, Mouikis, C, Spence, H, Kurth, W, Wygant, J, Skoug, RM, Larsen, BA, Reeves, GD, De Pascuale, S
JournalJournal of Geophysical Research: Space Physics
Pagination6585 - 6595
Date Published07/2019
Keywordscomposition; plasmasphere: ion; temperature; Van Allen Probes
AbstractWe analyze a database of Dynamics Explorer‐1 (DE‐1) Retarding Ion Mass Spectrometer densities and temperatures to yield the first explicit measure of how cold ion concentration depends on temperature. We find that cold H+ and He+ concentrations have very weak dependence on temperature, but cold O+ ion concentration increases steeply as these ions become warmer. We demonstrate how this result can aid in analyzing composition data from other satellites without spacecraft potential mitigation, by applying the result to an example using data from the Van Allen Probes mission. Measurement of light ion concentrations above 1 electron volt (eV) are a reasonable proxy for the concentrations of colder (eV) ions. Warmer O+ ion concentrations may be extrapolated to colder temperatures using our fit to the statistical distribution versus temperature.
Short TitleJ. Geophys. Res. Space Physics

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