Premium
Electrodynamics of a flux transfer event: Experimental test of the Southwood model
Author(s) -
Marchaudon A.,
Cerisier J.C.,
Greenwald R. A.,
Sofko G. J.
Publication year - 2004
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 - 10.1029/2004gl019922
Subject(s) - poynting vector , physics , flux (metallurgy) , ionosphere , meteorology , flow (mathematics) , convection , current (fluid) , mechanics , computational physics , geophysics , atmospheric sciences , magnetic field , materials science , quantum mechanics , metallurgy , thermodynamics
On 12 September 1999, a conjunction between two SuperDARN radars and the Ørsted satellite gave, for the first time, simultaneous access to the ionospheric convection enhancement and the field‐aligned currents (FACs) associated with a Flux Transfer Event. The radars observed an azimuthally elongated convection flow burst and the Ørsted satellite observed a series of successive small‐scale parallel currents alternating between downward and upward. The most poleward pair of currents, whose directions were in agreement with the Southwood model, was observed when Ørsted crossed the front edge of the flow burst. A quantitative comparison of the current density of each FAC and of the Pedersen current density indicates that the closure current for this FACs pair occurred inside the flow burst, confirming the validity of the Southwood model. The Poynting flux carried by the parallel currents was less than 1% of the power carried by the solar wind plasma.