Observations of dawn–dusk aligned polar cap aurora during the substorms of January 21, 2005
Review articleOpen access
A.M. Du - No affiliation found
2011/10/01 Full-length article DOI: 10.1016/j.pss.2011.06.021
Journal: Planetary and Space Science
AbstractA new type of polar cap aurora, dawn–dusk aligned polar cap aurora (DDAPCA), was detected during the exceptionally intense January 21, 2005 substorm (AEmax=3504 nT). The DDAPCA was located at very high latitude (>85° MLAT) in the polar cap region. As the interplanetary magnetic field (IMF) GSM By component rotated from a positive to a negative value, the DDAPCA tilt angle relative to the dawn–dusk direction rotated anticlockwise and reached ∼45°. It is speculated that the DDAPCA arises from the formation of an X-line in the distant (>80RE) tail due to polar cap magnetic field reconnection under unusually high solar wind compression conditions.
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