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Isolated Auroral Spots Observed by DMSP/SSUSI
Author(s) -
Zhou Su,
Luan Xiaoli,
Pierrard Viviane,
Han Desheng
Publication year - 2019
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1029/2019ja026853
Subject(s) - physics , electron , ion , ring current , geomagnetic storm , atomic physics , cyclotron , astrophysics , magnetic field , geophysics , magnetosphere , plasma , earth's magnetic field , nuclear physics , quantum mechanics
This work reports auroral spots event observed by the SSUSI instruments on board the DMSP spacecraft between 22 and 23 July 2009 during the recovery phase of a moderate magnetic storm. The spots were observed between 18:00 and 02:00 magnetic local time and stayed at ~60° magnetic latitude. They lasted for ~10 hr and corotated with ~64% of the Earth's rotational speed. In situ observations indicate that the isolated auroral spots were produced by energetic ions at energies between 10 and 240 keV, with significantly anisotropic electron (30–300 keV) precipitations. It is expected that the energetic ions originate from the ring current and can be scattered by the EMIC waves through cyclotron resonance. The energetic electrons can be precipitated by the nonresonant interaction between the electrons and EMIC waves, which is suggested by previous works.