12-hour case study of auroral phenomena in the midnight sector: Electrojet and precipitating particle characteristics
Airborne observations of auroral activity at midnight were conducted for a period of 9 hours by employing an ionospheric sounder and all-sky cameras. During the observation period, two substorms occurred. The first substorm was assciated with a compression of the magnetosphere (as measured by Dst) and with oscillations of the earth's bow shock. At this time, auroral activity was characterized by a series of poleward and equatorward motions and by the absence of a breakup phase. Magnetic disturbances were confined to a small region in the midnight sector. The second auroral substorm displayed many of the features assocated with a large-scale polar magnetic substorm. For selected times the locations of the eastward and westward electrojets were inferred from a number of high-latitude magnetic records. All-sky photographs and ionosonde data indicate that the poleward edge of the westward electrojet was bounded by a westward moving auroral surge accompanied by a strong sporadic E ionization. The equatorward electrojet boundary was less well defined by visual auroral forms. Soft particle spectrometer measurements from the Isis 2 satellite were made in conjunction with the aircraft measurements and indicate that large fluxes of field-aligned electrons gave rise to the bright auroral surge, more isotropic fluxes of less energetic electrons contributing to the auroral E layer.
- Research Organization:
- Airforce Geophysics Laboratories, Hanscom Air Force Base, Massachusetts 01731
- OSTI ID:
- 7214281
- Journal Information:
- J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 82:25; ISSN JGREA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
Ionospheric
& Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AURORAE
AURORAL ZONES
CHARGED-PARTICLE PRECIPITATION
CURRENTS
E REGION
EARTH ATMOSPHERE
ELECTRIC CURRENTS
ELECTROJETS
ELECTRON PRECIPITATION
IONOSPHERE
IONOSPHERIC STORMS
MAGNETIC BAYS
MAGNETIC STORMS
PLANETARY IONOSPHERES
POLAR-CAP AURORAE