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Plasmaspheric Density Troughs: Global IMAGE EUV Observations and Analysis via Global Core Plasma ModelingTo date, the IMAGE EUV camera has observed several plasmaspheric density trough features inside the plasmapause under a wide range of geomagnetic activity. From the perspective of EUV, a density trough feature appears as a channel of diminished pixel counts which spans a width of L-shell (DELTA L) and magnetic local time (MLT) inside the plasmapause. Plasmaspheric density troughs are found to be morphologically complex possessing considerable spatial and temporal variability. We present an analysis of the evolution of trough DELTA L and MLT extent as functions of associated D (sub ST) and K (sub p) history. Trough features range in size from 0.16 less than or equal to DELTA L less than or equal to 1.2 with azimuthal extent from 1500 less than or equal to MLT less than or equal to 1200. All cases of plasmaspheric density troughs studied to date appear to have evolved as a result of the inner edge of the afternoon/evening plasma drainage plume being wrapped around through the nightside plasmasphere. The structure of plasmaspheric density trough features is further probed by analyzing simulated EUV images produced by forward modeling artificially introduced regions of depleted density into both static and dynamic global core plasmaspheric models. Forward modeling suggests that (1) L-shell refilling of density troughs during storm recovery can be modeled as filling from the ionosphere toward the equator (i.e., bottom-up refilling), and (2) that an erosion process is operating within flux tubes beyond the outer L-shell wall of the observed density troughs.
Document ID
20020050356
Acquisition Source
Marshall Space Flight Center
Document Type
Conference Paper
Authors
Adrian, M. L.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Gallagher, D. L.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Green, J. L.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Sandel, B. R.
(Arizona Univ. Tucson, AZ United States)
Six, N. Frank
Date Acquired
August 20, 2013
Publication Date
January 1, 2002
Subject Category
Geophysics
Meeting Information
Meeting: Magnetospheric Imaging Workshop
Location: Yosemite National Park, CA
Country: United States
Start Date: February 5, 2002
End Date: February 8, 2002
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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