Variations of oxygen charge state abundances in the global magnetosphere, as observed by Polar

• Published in: Journal of geophysical research. Space physics Vol. 121; no. 2; pp. 1091 - 1113
• Main Authors: Allen, R. C., Livi, S. A., Goldstein, J.
• Format: Journal Article
• Language: English
• Published: Washington Blackwell Publishing Ltd 01-02-2016
• Subjects: Charge; Charged particles; Earth magnetosphere; Exchanging; Geomagnetism; ionospheric outflow; Ionospherics; Ions; magnetosphere; Magnetospheres; Oxygen; oxygen charge states; plasma convection; Polar; Populations; Solar wind; solar wind penetration; Spacecraft
• ISSN: 2169-9380; 2169-9402
• DOI: 10.1002/2015JA021765

Geomagnetically trapped oxygen ions of solar and ionospheric origin have previously been observed in the Earth's magnetosphere. Early observations from Active Magnetospheric Particle Tracer Explorers/CCE have studied this distribution within a limited spatial range of L shells over all magnetic local times (MLT). This study expands on these early results using observations from the Polar spacecraft. The distributions by charge state show O6+, from the solar wind, charge exchanging into O5+, O4+, and O3+ as the ion populations drift to lower L shells. Meanwhile, ionospheric O+ and O2+ are primarily seen at low L shells and may also play a role in O3+ populations. We also present here the Dst, Vsw∗Bz, and AE dependencies of oxygen charge states (O+ through O6+) in MLT and L shell in the magnetosphere of the Earth. The distributions of these charge states provide insight into the injection and energization of both ionospheric oxygen as well as solar wind ions inside the magnetosphere.
Key Points
The distribution of oxygen charge states are studied in the global magnetosphere using Polar data
These distributions are investigated in both L shell and magnetic local time
Distributions of ionospheric O+ and solar wind O6+ are studied against Dst, Vsw∗Bz, and AE