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Electron acceleration in the auroral current circuit
Author(s) -
Rönnmark Kjell
Publication year - 1999
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 - 10.1029/1999gl900133
Subject(s) - electron , physics , current (fluid) , computational physics , plasma , current density , magnetohydrodynamics , atomic physics , acceleration , electron density , electron precipitation , magnetosphere , classical mechanics , nuclear physics , quantum mechanics , thermodynamics
Understanding the mechanism supporting the potential drops that accelerate electrons into discrete auroral arcs has been an outstanding problem in space physics for decades. A few thousand kilometers above auroral arcs the electron density often is well below 10 6 m −3 , and the parallel current density into discrete auroral arcs is often a few µA/m². To carry this current in such a low density plasma, the electrons must be accelerated to high energies, and kV potential drops can be supported by electron inertia alone. We describe how an equatorial MHD generator sets up the auroral current system and creates the parallel potential drop that accelerates auroral electrons to keV energies.