|
Read Full Article (file size: 1884126 bytes) Cited by
JOURNAL OF GEOPHYSICAL RESEARCH,
VOL. 107, NO. A9,
1251,
doi:10.1029/2001JA007554,
2002
Interplanetary magnetic field control of afternoon-sector detached proton auroral arcs
J. L. Burch
Southwest Research Institute,
San Antonio,
Texas,
USA
W. S. Lewis
Southwest Research Institute,
San Antonio,
Texas,
USA
T. J. Immel
University of California,
Berkeley,
California,
USA
P. C. Anderson
Aerospace Corporation,
El Segundo,
California,
USA
H. U. Frey
University of California,
Berkeley,
California,
USA
S. A. Fuselier
Lockheed Martin Advanced Technology Center,
Palo Alto,
California,
USA
J.-C. Gérard
University of Liège,
Liège,
Belgium
S. B. Mende
University of California,
Berkeley,
California,
USA
D. G. Mitchell
Applied Physics Laboratory,
Johns Hopkins University,
Laurel,
Maryland,
USA
M. F. Thomsen
Los Alamos National Laboratory,
Los Alamos,
New Mexico,
USA
Abstract
Data from the Far Ultraviolet Imager (FUV) on the Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) satellite show
that subauroral proton arcs appear in the afternoon sector during geomagnetically disturbed periods when the interplanetary
magnetic field rotates either from south to north or from west to east and when the magnetosphere is moderately compressed.
Time series of proton aurora images show that the proton emissions are generally aligned along the equatorward part of the
auroral oval. However, when interplanetary magnetic field (IMF) Bz changes from negative to positive the auroral oval contracts toward higher latitudes while the ring current proton precipitation
remains stationary, resulting in a separation of several degrees between the latitude of the new oval position and a subauroral
proton arc in the afternoon sector. A similar effect occurs when IMF By rotates from negative to positive, in which case the oval in the afternoon sector retreats toward higher latitudes, again
leaving a separation between the oval and the subauroral proton arc of several degrees. Comparisons with low-altitude and
geosynchronous satellite data show that the subauroral proton arc is caused by the precipitation of protons with energies
from several keV to 30 keV and is likely associated with the existence of a plasmaspheric “drainage plume.” In contrast, the
proton emissions along the main oval are caused by protons with energies generally less than 10 keV.
Published 25
September
2002.
Index Terms: 2704 Magnetospheric Physics: Auroral phenomena (2407); 2736 Magnetospheric Physics: Magnetosphere/ionosphere interactions; 2716 Magnetospheric Physics: Energetic particles, precipitating.
Read Full Article (file size: 1884126 bytes) Cited by
Citation: Burch, J. L., W. S. Lewis, T. J. Immel, P. C. Anderson, H. U. Frey, S. A. Fuselier, J.-C. Gérard, S. B. Mende, D. G. Mitchell, and M. F. Thomsen
(2002),
Interplanetary magnetic field control of afternoon-sector detached proton auroral arcs,
J. Geophys. Res.,
107(A9),
1251,
doi:10.1029/2001JA007554.
Copyright 2002 by the American Geophysical Union.
|