Auroral and sub-auroral phenomena: an electrostatic picture
Many auroral and sub-auroral phenomena are manifestations of an underlying magnetosphere-ionosphere coupling. In the electrostatic perspective the associated auroral current circuit describes how the generator (often in the magnetosphere) is connected to the load (often in the ionosphere) through...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2010-02-01
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| Series: | Annales Geophysicae |
| Online Access: | https://www.ann-geophys.net/28/633/2010/angeo-28-633-2010.pdf |
| Summary: | Many auroral and sub-auroral phenomena are manifestations of an underlying
magnetosphere-ionosphere coupling. In the electrostatic perspective the associated auroral current
circuit describes how the generator (often in the magnetosphere) is connected
to the load (often in the ionosphere) through field-aligned currents. The present paper
examines the generic properties of the current continuity equation that
characterizes the auroral circuit. The physical role of the various elements
of the current circuit is illustrated by considering a number of
magnetospheric configurations, various auroral current-voltage relations, and different
types of behaviour of the ionospheric conductivity. Based on realistic
assumptions concerning the current-voltage relation and the ionospheric conductivity, a
comprehensive picture of auroral and sub-auroral phenomena is presented,
including diffuse aurora, discrete auroral arcs, black aurora, and subauroral
ion drift. The electrostatic picture of field-aligned potential differences, field-aligned currents,
ionospheric electric fields and plasma drift, and spatial scales for all
these phenomena is in qualitative agreement with observations. |
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| ISSN: | 0992-7689 1432-0576 |