Journal article
Flux Enhancements of Field-Aligned Low-Energy O+ Ion (FALEO) in the Inner Magnetosphere: A Possible Source of Warm Plasma Cloak and Oxygen Torus
Journal of geophysical research. Space physics, Vol.127(3), pp.e2021JA030008-n/a
03/01/2022
DOI: 10.1029/2021JA030008
Abstract
Flux enhancements of field-aligned low-energy O+ ion (FALEO) are simultaneously observed by Arase, Van Allen Probes A and B in the nightside inner magnetosphere during 05-07 UT on September 22, 2018. FALEOs appear after a magnetic dipolarization signature with approximately 6-20 min delay. It has the energy-dispersion signature from a few keV to similar to 100 eV only in the direction parallel to the magnetic field at Arase, while it decreases its energy from a few keV down to 10 eV in both the parallel and antiparallel directions at Probes A and B. We perform a numerical simulation to trace trajectories of test O+ ions in a model magnetosphere, which are launched from above the ionosphere 3-15 min after a substorm. Flying virtual satellites that have the same orbits as the real satellites, we create virtual energy-time spectrograms of O+ ions to compare with the observed ones. Results show a very good correspondence between them, indicating that FALEOs originate from ionospheric O+ ions that are extracted from the upper ionosphere at substorm onset and flow along the magnetic field toward the geomagnetic equator. It is also revealed that 3-9 hr after their launch, test O+ ions less than 400 eV have a spatial distribution in the inner magnetosphere which is similar to those of the warm plasma cloak and the oxygen torus. We therefore conclude that FALEO is a source of those cold ion populations.
Details
- Title: Subtitle
- Flux Enhancements of Field-Aligned Low-Energy O+ Ion (FALEO) in the Inner Magnetosphere: A Possible Source of Warm Plasma Cloak and Oxygen Torus
- Creators
- M. Nose - Nagoya UniversityA. Matsuoka - Kyoto UniversityY. Miyoshi - Nagoya UniversityK. Asamura - Institute of Space and Astronautical ScienceT. Hori - Nagoya UniversityM. Teramoto - Kyushu Institute of TechnologyI. Shinohara - Institute of Space and Astronautical ScienceM. Hirahara - Nagoya UniversityC. A. Kletzing - University of IowaC. W. Smith - Univ New Hampshire, Inst Study Earth Oceans & Space, Durham, NH USAR. J. MacDowall - Goddard Space Flight CenterH. E. Spence - University of New HampshireG. D. Reeves - Los Alamos National LaboratoryJ. W. Gjerloev - Johns Hopkins University Applied Physics Laboratory
- Resource Type
- Journal article
- Publication Details
- Journal of geophysical research. Space physics, Vol.127(3), pp.e2021JA030008-n/a
- Publisher
- Amer Geophysical Union
- DOI
- 10.1029/2021JA030008
- ISSN
- 2169-9380
- eISSN
- 2169-9402
- Number of pages
- 19
- Grant note
- 21H01147; 17K18804 / Grants-in-Aid for Scientific Research; Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT); Japan Society for the Promotion of Science; Grants-in-Aid for Scientific Research (KAKENHI) 16H04057; 21H01147; 15H05815; 20H01959; 17K18804; 16H06286 / Japan Society for the Promotion of Science (JSPS); Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT); Japan Society for the Promotion of Science
- Language
- English
- Date published
- 03/01/2022
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984428664602771
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