DMSP F7 observations of a substorm field-aligned current

Journal Article · Fri Nov 01 04:00:00 EST 1991 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/91JA01984· OSTI ID:5694777

Lopez, R E ^[1]; Spence, H E ^[2]; Meng, C I ^[3]

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1. Applied Research Corp., Landover, MD (United States)
2. Aerospace Corp., Los Angeles, CA (United States)
3. Johns Hopkins Univ., Laurel, MD (United States)

In this paper the authors present observations of a substorm field-aligned current (FAC) system that DMSP F7 traversed just after 0300 UT on April 25, 1985. Ground magnetometer data show that a major substorm was in progress at that time and that DMSP F7 flew through a region of predominantly upward FAC. The DMSP F7 magnetic field data are consistent with this interpretation. The precipitating particle data suggest that there were three distinct large-scale FAC systems. In ascending latitude these were a downward current, an upward current, and a paired upward/downward current system. They identify the first current, which was coincident with the diffuse aurora, as region 2. The next (upward) FAC was coincident with a spatially unstructured region of energetic ({approximately}12 keV) electron precipitation. This was the substorm-associated FAC that made up part of the current wedge. The upward/downward current pair was coincident with a region of highly structured precipitation. They suggest that these currents may have been the duskside region 1 and, poleward of that, the extension of the dawnside region 1. The particle data show that the upward substorm FAC maps to the neutral sheet at 6.9 R{sub E}. While one should be cautious in stressing results obtained by mapping model field lines, their result is consistent with scenarios for substorms which postulate a disruption and diversion of the near-Earth cross-tail current.

• OSTI ID: 5694777
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 96:A11; ISSN 0148-0227; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

661320* -- Auroral
Ionospheric
& Magnetospheric Phenomena-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AURORAE
BOUNDARY LAYERS
CHARGED-PARTICLE PRECIPITATION
CURRENTS
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
ELECTRIC CURRENTS
ELECTRON PRECIPITATION
GEOMAGNETIC FIELD
LAYERS
MAGNETIC BAYS
MAGNETIC FIELD CONFIGURATIONS
MAGNETIC FIELDS
MAGNETOTAIL
ORIGIN
SATELLITES