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Statistical analysis of the sources of the cross‐polar potential for southward IMF, based on particle precipitation characteristics
Author(s) -
Sundberg K. Å. T.,
Blomberg L. G.,
Cumnock J. A.
Publication year - 2008
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2008gl033383
Subject(s) - dynamo , polar , convection , geophysics , polar cap , magnetosphere , ionosphere , physics , northern hemisphere , magnetic reconnection , electron precipitation , atmospheric sciences , geology , meteorology , magnetic field , astronomy , quantum mechanics
There are several proposed physical processes which may contribute to the cross‐polar potential and thus drive ionospheric convection around the polar caps. It is generally believed that magnetic reconnection is the dominant process, however dynamos such as viscous interaction and impulsive penetration are other possible contributors. A comprehensive statistical study has been conducted using data from the DMSP F13 satellite for passages along the northern hemisphere dawn‐dusk meridian, with focus on typical two‐cell convection patterns during times of steady southward IMF conditions. The results show that the low‐latitude dynamo (viscous interaction or reconnection in the LLBL) on average accounts for only 1–2 kV of the total potential drop, values lower than those previously predicted. At rare occasions this dynamo can be a significant source of energy, however, contributing to more than 20 kV of the cross‐polar potential.