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Empirical Modeling of the Storm Time Innermost Magnetosphere Using Van Allen Probes and THEMIS Data: Eastward and Banana CurrentsThe structure of storm time currents in the inner magnetosphere, including its innermost region inside 4R(sub E), is studied for the first time using a modification of the empirical geomagnetic field model TS07D and new data from Van Allen Probes and Time History of Events and Macroscale Interactions during Substorms missions. It is shown that the model, which uses basis-function expansions instead of ad hoc current modules to approximate the magnetic field, consistently improves its resolution and magnetic field reconstruction with the increase of the number of basis functions and resolves the spatial structure and evolution of the innermost eastward current. This includes a connection between the westward ring current flowing largely at R > or approx. 3R(sub E) and the eastward ring current concentrated at R < or approx. 3R(sub E) resulting in a vortex current pattern. A similar pattern coined 'banana current' was previously inferred from the pressure distributions based on the energetic neutral atom imaging and first-principles ring current simulations. The morphology of the equatorial currents is dependent on storm phase. During the main phase, it is complex, with several asymmetries forming banana currents. Near SYM-H minimum, the banana current is strongest, is localized in the evening-midnight sector, and is more structured compared to the main phase. It then weakens during the recovery phase resulting in the equatorial currents to become mostly azimuthally symmetric.
Document ID
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
External Source(s)
Stephens, G. K.
(Johns Hopkins Univ. Laurel, MD, United States)
Sitnov, M. I.
(Johns Hopkins Univ. Laurel, MD, United States)
Ukhorskiy, A. Y.
(Johns Hopkins Univ. Laurel, MD, United States)
Roelof, E. C.
(Johns Hopkins Univ. Laurel, MD, United States)
Tsyganenko, N. A.
(Saint Petersburg State Univ. Saint Petersburg, Russian Federation)
Le, G.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Date Acquired
April 7, 2017
Publication Date
January 6, 2016
Publication Information
Publication: Journal of Geophysical Research: Space Physics
Publisher: AGU
Volume: 121
Issue: 1
ISSN: 2169-9380
e-ISSN: 2169-9402
Subject Category
Space Sciences (General)
Report/Patent Number
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