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AGU: Journal of Geophysical Research, Space Physics

 

Index Terms

  • Magnetospheric Physics: Auroral phenomena
  • Magnetospheric Physics: Solar wind/magnetosphere interactions
  • Magnetospheric Physics: Magnetospheric configuration and dynamics
  • Magnetospheric Physics: Magnetopause, cusp, and boundary layers
Abstract
Cited By (2)
 

Abstract

Southern Hemisphere poleward moving auroral forms

E. E. Drury

Space Sciences Laboratory, University of California Berkeley, Berkeley, California, USA

S. B. Mende

Space Sciences Laboratory, University of California Berkeley, Berkeley, California, USA

H. U. Frey

Space Sciences Laboratory, University of California Berkeley, Berkeley, California, USA

J. H. Doolittle

Lockheed Palo Alto Research Laboratories, Palo Alto, California, USA

This paper presents a statistical study of Southern Hemisphere poleward moving auroral forms (PMAFs) using optical data from the US Automatic Geophysical Observatory network in Antarctica. These Southern Hemisphere events are compared with Northern Hemisphere PMAFs, which have previously been observed during varied interplanetary magnetic field (IMF) configurations. The frequency of PMAF occurrence is studied as a function of IMF orientation and magnetic local time. Southern Hemisphere PMAFs are biased to Bz < 0 constituting 62% of events, but are frequently observed during conditions of Bz > 0 constituting 38% of events. Southern Hemisphere PMAFs share a similar IMF Bz dependence with Northern Hemisphere events [e.g., Fasel, 1995 ]. The primary modulator of PMAFs was found to be IMF By, which was negative for 81% of events. Although the average background IMF was biased to By < 0, we find significant enhancement during By < 0 after this bias was removed. In a statistical study of Northern Hemisphere events, Fasel [1995] found 77% of events occur during positive By. PMAFs appear to have an antisymmetric By dependence between hemispheres. We find By < 0 (By > 0) enhances the observation of PMAFs in the prenoon (postnoon) region, consistent with the release of magnetic stress. A morning bias of Southern Hemisphere PMAFs is observed, consistent with Northern Hemisphere events.

Published 14 March 2003.

Citation: Drury, E. E., S. B. Mende, H. U. Frey, and J. H. Doolittle (2003), Southern Hemisphere poleward moving auroral forms, J. Geophys. Res., 108(A3), 1114, doi:10.1029/2001JA007536.

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