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Titel |
Derivation of inner magnetospheric electric field (UNH-IMEF) model using Cluster data set |
VerfasserIn |
H. Matsui, P. A. Puhl-Quinn, V. K. Jordanova, Y. Khotyaintsev, P.-A. Lindqvist, R. B. Torbert |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
0992-7689
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Digitales Dokument |
URL |
Erschienen |
In: Annales Geophysicae ; 26, no. 9 ; Nr. 26, no. 9 (2008-09-23), S.2887-2898 |
Datensatznummer |
250016235
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Publikation (Nr.) |
copernicus.org/angeo-26-2887-2008.pdf |
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Zusammenfassung |
We derive an inner magnetospheric electric field (UNH-IMEF) model at L=2–10
using primarily Cluster electric field data for more than 5 years between
February 2001 and October 2006. This electric field data set is divided into
several ranges of the interplanetary electric field (IEF) values measured by
ACE. As ring current simulations which require electric field as an input
parameter are often performed at L=2–6.6, we have
included statistical results from ground radars and low altitude satellites
inside the perigee of Cluster in our data set (L~4). Electric potential
patterns are
derived from the average electric fields by solving an inverse problem. The
electric potential pattern for small IEF values is probably affected by the
ionospheric dynamo. The magnitudes of the electric field increase around
the evening local time as IEF increases, presumably due to the
sub-auroral polarization stream (SAPS). Another region with enhanced electric
fields during large IEF periods is located around 9 MLT at L>8, which is
possibly related to solar
wind-magnetosphere coupling. Our potential patterns are consistent with those
derived from self-consistent simulations. As the potential patterns can be
interpolated/extrapolated to any discrete IEF value within measured ranges, we
thus derive an empirical electric potential model. The performance of the
model is evaluated by comparing the electric field derived from the model with
original one measured by Cluster and mapped to the equator. The model is open
to the public through our website. |
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