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AGU: Journal of Geophysical Research, Space Physics

 

Keywords

  • subauroral polarization stream
  • cross-polar cap potential
  • subauroral conductance

Index Terms

  • Ionosphere: Electric fields
  • Ionosphere: Ionosphere/magnetosphere interactions
  • Ionosphere: Plasma convection
  • Magnetospheric Physics: Field-aligned currents and current systems
  • Magnetospheric Physics: Magnetosphere: inner
Abstract
Cited By (0)
 

Abstract

Statistical study of the subauroral polarization stream: Its dependence on the cross–polar cap potential and subauroral conductance

Hui Wang

School of Electronic Information, Wuhan University, Wuhan, China

Aaron J. Ridley

Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Ann Arbor, Michigan, USA

Hermann Lühr

GeoForschungsZentrum, Potsdam, Germany

Michael W. Liemohn

Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Ann Arbor, Michigan, USA

Shu Y. Ma

School of Electronic Information, Wuhan University, Wuhan, China

Two years of DMSP ion drift meter measurements have been used for a focused study of the subauroral polarization streams (SAPS). The main emphasis is on the effects of the cross–polar cap potential (CPCP) and the subauroral flux tube–integrated conductivity (that is, whether or not the northern and/or southern ionospheric footprint of the flux tube is sunlit or not) on the SAPS spatial distribution. For higher flux tube–integrated conductivity the SAPS tend to occur more poleward than for lower conductivity. The magnetic latitude (MLAT) difference can reach several degrees at most. The dependence of SAPS location on geomagnetic activity is also studied, and it is found that the SAPS magnetic latitude exhibits an exponential relation with Dst. When Dst ≤ −200 nT the SAPS tend to occur at 48° MLAT. The CPCP averaged over 15 min prior to the SAPS correlates best with the SAPS peak velocities. The high-latitude CPCP has a stronger effect on the SAPS velocities for low integrated conductivity than for high conductivity. Finally, the observations show that there is a good anticorrelation between the subauroral integrated conductivity and the SAPS velocity, which confirms previous model results.

Received 23 June 2008; accepted 17 September 2008; published 30 December 2008.

Citation: Wang, H., A. J. Ridley, H. Lühr, M. W. Liemohn, and S. Y. Ma (2008), Statistical study of the subauroral polarization stream: Its dependence on the cross–polar cap potential and subauroral conductance, J. Geophys. Res., 113, A12311, doi:10.1029/2008JA013529.

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