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Comparison Between Vortices Created and Evolving During Fixed and Dynamic Solar Wind ConditionsWe employ Magnetohydrodynamic (MHD) simulations to examine the creation and evolution of plasma vortices within the Earth's magnetosphere for steady solar wind plasma conditions. Very few vortices form during intervals of such solar wind conditions. Those that do remain in fixed positions for long periods (often hours) and exhibit rotation axes that point primarily in the x or y direction, parallel (or antiparallel) to the local magnetospheric magnetic field direction. Occasionally, the orientation of the axes rotates from the x direction to another direction. We compare our results with simulations previously done for unsteady solar wind conditions. By contrast, these vortices that form during intervals of varying solar wind conditions exhibit durations ranging from seconds (in the case of those with axes in the x or y direction) to minutes (in the case of those with axes in the z direction) and convect antisunward. The local-time dependent sense of rotation seen in these previously reported vortices suggests an interpretation in terms of the Kelvin-Helmholtz instability. For steady conditions, the biggest vortices developed on the dayside (about 6R(E) in diameter), had their rotation axes aligned with the y direction and had the longest periods of duration. We attribute these vortices to the flows set up by reconnection on the high latitude magnetopause during intervals of northward Interplanetary Magnetic Field (IMF) orientation. This is the first time that vortices due to high-latitude reconnection have been visualized. The model also successfully predicts the principal characteristics of previously reported plasma vortices within the magnetosphere, namely their dimension, flow velocities, and durations.
Document ID
20140017490
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
Collado-Vega, Yaireska M.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Kessel, R. L.
(NASA Headquarters Washington, DC United States)
Sibeck, David Gary
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Kalb, V. L.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Boller, R. A.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Rastaetter, L.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Date Acquired
December 17, 2014
Publication Date
August 30, 2013
Publication Information
Publication: Annales Geophysicae
Publisher: Open Access Journal of the European Geosciences Union
Volume: 31
Issue: 8
Subject Category
Geosciences (General)
Report/Patent Number
GSFC-E-DAA-TN14657
Distribution Limits
Public
Copyright
Public Use Permitted.
Keywords
solar wind
dynamic
vortices
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