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Magnetic latitude dependence of oxygen charge states in the global magnetosphere: Insights into solar wind‐originating ion injection
Author(s) -
Allen R. C.,
Livi S. A.,
Vines S. K.,
Goldstein J.
Publication year - 2016
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1002/2016ja022925
Subject(s) - magnetosphere , solar wind , polar wind , physics , magnetopause , ionosphere , magnetosphere of jupiter , atmospheric sciences , geophysics , plasma , computational physics , atomic physics , nuclear physics
Understanding the sources and subsequent evolution of plasma in a magnetosphere holds intrinsic importance for magnetospheric dynamics. Previous studies have investigated the balance of ionospheric‐originating heavy ions (low charge state) from those of solar wind origin (high charge state) in the magnetosphere of Earth. These studies have suggested a variety of entry mechanisms for solar wind ions to penetrate into the magnetosphere. Following from recently published distributions for oxygen charge states observed by the Polar spacecraft, this paper investigates oxygen charge state flux distributions versus L shell and magnetic latitude. By showing these distributions in this frame, and binning by various proxies for magnetospheric dynamics ( D s t , A E , V SW ∗ B Z , P dyn ), insight has been gained into the underlying physics at play for oxygen injection. Ionospheric‐originating oxygen is observed to depend predominantly on D s t , whereas solar wind‐originating oxygen is observed to have a strong dependence on solar wind dynamic pressure ( P dyn ) at the flanks and on V SW ∗ B Z at the dayside. This suggests that both Kelvin‐Helmholtz instabilities and reconnection play major roles in solar wind ion penetration into a magnetosphere. Additionally, the near‐Earth magnetotail reconnection site does not seem to be a major injection site of solar wind‐originating plasma in the 1 to 200 keV/e energy range.