Premium
Open magnetic flux and magnetic flux closure during sawtooth events
Author(s) -
Hubert B.,
Milan S. E.,
Grocott A.,
Cowley S. W. H.,
Gérard J. C.
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 - 10.1029/2008gl036374
Subject(s) - substorm , magnetosphere , sawtooth wave , geophysics , physics , flux (metallurgy) , magnetic reconnection , solar wind , magnetic flux , ionosphere , plasmoid , astrophysics , atmospheric sciences , plasma , magnetic field , materials science , quantum mechanics , computer science , metallurgy , computer vision
We use IMAGE‐FUV observations of the polar aurora and measurements of the ionospheric convection from the SuperDARN radar network to study several sawtooth events previously reported in the literature. We estimate the amount of open magnetic flux in the Earth magnetosphere during a significant part of these sawtooth intervals as well as the magnetic flux opening and closure rates, that is, the dayside and nightside reconnection rates. We find that during the sawtooth intervals the magnetosphere is highly loaded with open flux as a result of the strongly southward IMF carried by the solar wind during these intervals. The magnetosphere tries to relax to a less loaded configuration through a sequence of substorm expansions. However, these substorms do not necessarily evolve to their end before reintensification of nightside reconnection occurs in response to continued loading of the magnetosphere on the dayside.