Reverse convection

Journal Article · Tue Dec 01 04:00:00 EST 1992 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/92JA01532· OSTI ID:7061817

Crooker, N U ^[1]

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1. Univ. of California, Los Angeles (United States)

A model of magnetospheric topology for periods when the interplanetary magnetic field (IMF) points northward indicates that reverse convection can readily occur when Earth's dipole or the IMF tilt toward or away from the Sun. In either case, all or part of one tail lobe drapes over the dayside, and the magnetopause merging voltage is applied directly to the ionosphere in that lobe only, to the center or nightside of the polar cap. The overdraped lobe forms layers both earthward and sunward of the magnetopause, similar to layers observed during periods of northward IMF. The model predicts two quasi-steady state patterns of reverse convection: (1) lobe cells in the polar cap of the overdraped lobe, generated by open-to-open flux transfer at the magnetopause and (2) merging cells in both polar caps, generated by closed-to-open flux transfer at the magnetopause and balanced open-to-closed transfer at an internal reconnection site, comparable to the tail merging site for southward IMF. The model also predicts transitional patterns of reverse convection for growing and shrinking polar caps in response to changes in dipole tilt and B[sub x] and in response to a sudden transition from southward to northward IMF. The model predicts theta aurora bar formation on the dawnside polar cap boundary when activation of the internal reconnection site ends polar cap growth. In this view the theta aurora becomes the northward IMF counterpart to substorms.

• OSTI ID: 7061817
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 97:A12; ISSN JGREA2; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

661320* -- Auroral
Ionospheric
& Magnetospheric Phenomena-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AURORAE
CONVECTION
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
ENERGY TRANSFER
HEAT TRANSFER
INTERPLANETARY MAGNETIC FIELDS
IONOSPHERE
MAGNETIC FIELDS
MAGNETOPAUSE
MASS TRANSFER
MATHEMATICAL MODELS
MATHEMATICS
PLANETARY IONOSPHERES
POLAR-CAP AURORAE
TOPOLOGY