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Storm phase dependence of ion outflow: Statistical signatures obtained by IMAGE/LENA
Author(s) -
Kunori T.,
Nosé M.,
Taguchi S.,
Hosokawa K.,
Collier M. R.,
Moore T. E.
Publication year - 2007
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2007gl029877
Subject(s) - outflow , solar wind , storm , physics , energetic neutral atom , geomagnetic storm , flux (metallurgy) , phase (matter) , ion , magnetopause , geophysics , substorm , magnetosphere , exosphere , van allen probes , spacecraft , atmospheric sciences , astrophysics , meteorology , astronomy , van allen radiation belt , plasma , materials science , nuclear physics , quantum mechanics , metallurgy
The low‐energy neutral atom (LENA) imager on board the Imager for Magnetopause‐to‐Aurora Global Exploration (IMAGE) spacecraft can observe energetic neutral atoms (ENA) of 10 eV to a few keV generated by upflowing ions through charge exchange with the Earth's exosphere. Using IMAGE/LENA data, we statistically analyzed behaviors of the ion outflow in the main and recovery phases of the magnetic storms from June 2000 to December 2001. Results show that during the main phase, most of ENA emissions from the Earth's direction are accompanied by the solar wind dynamic pressure (P dy ) enhancements. For the recovery phase, there are no such tendencies. Instead, the ENA flux shows large values at the beginning of the recovery phase, and then decreases with the storm recovery. These results suggest that the dominant mechanism responsible for the ion outflow during the magnetic storms can be totally different between the two phases.