Observation of dayside subauroral proton flashes with the IMAGE-FUV imagers

B. Hubert, J. C. Gerard, S. A. Fuselier, S. B. Mende


A detailed description of an intense flash of auroral emissions that occurs
equatorward of the dayside auroral oval observed with the IMAGE-FUV imagers is
presented. The comparison of simultaneous snapshots of this subauroral flash
obtained with the three FUV cameras indicates that proton precipitation is
dominant. This transient proton aurora is triggered by the sudden increase of a
solar wind dynamic pressure pulse. It occurs on closed field lines mapping to
the equatorial plane at distances as small as ~4 RE. A second similar event is
presented, and several other cases are mentioned. These shock induced transcient
emissions develop with a time scale of a few minutes (typically ~5 min), and
have a relaxation time on the order of �`10 minutes. 

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Geophysical Research Letters, 30, 1145, 10.1029/2002GL016464, 2003