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Ann. Geophys., 20, 1603-1616, 2002
www.ann-geophys.net/20/1603/2002/
© European Geosciences Union 2002
A hybrid simulation model for a stable auroral arc
P. Janhunen1 and A. Olsson2
1Finnish Meteorological Institute, Geophysical Research, Helsinki, Finland
2Swedish Institute of Space Physics, Uppsala Division, Uppsala, Sweden
Correspondence to: P. Janhunen (pekka.janhunen@fmi.fi)
Abstract. We present a new type of hybrid simulation
model, intended to simulate a single stable auroral arc in the
latitude/altitude plane. The ionospheric ions are treated as particles, the
electrons are assumed to follow a Boltzmann response and the magnetospheric
ions are assumed to be so hot that they form a background population unaffected
by the electric fields that arise. The system is driven by assumed parallel
electron energisation causing a primary negative charge cloud and an associated
potential structure to build up. The results show how a closed potential
structure and density depletion of an auroral arc build up and how they decay
after the driver is turned off. The model also produces upgoing energetic ion
beams and predicts strong static perpendicular electric fields to be found in a
relatively narrow altitude range (~ 5000–11 000 km).
Key words. Magnetospheric physics
(magnetosphere-ionosphere interactions; auroral phenomena) – Space plasma
physics (numerical simulation studies)
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