Observations of centrifugal acceleration during compression of magnetosphere
Centrifugal acceleration of escaping ionospheric plasma is one of the important and fundamental processes responsible for energizing and transporting ionospheric plasma to all regions of the magnetosphere. Normally this mechanism operates over extremely large distances. Because of this feature and l...
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Published in | Geophysical research letters Vol. 27; no. 7; pp. 915 - 918 |
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Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
Washington, DC
Blackwell Publishing Ltd
01.04.2000
American Geophysical Union |
Subjects | |
Online Access | Get full text |
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Summary: | Centrifugal acceleration of escaping ionospheric plasma is one of the important and fundamental processes responsible for energizing and transporting ionospheric plasma to all regions of the magnetosphere. Normally this mechanism operates over extremely large distances. Because of this feature and limitations in particle instrumentation, it has not been possible to directly confirm from in‐situ plasma measurements the very specific predictions made by basic plasma theory about centrifugal acceleration. We report here data obtained near Polar satellite apogee over the northern polar cap during a magnetospheric compression event that occurred on September 24, 1998. Between 2345:18 and 2347:18 UT the magnetic field rotated by about 20° and increased in intensity. The Toroidal Imaging Mass‐Angle Spectrograph (TIMAS) instrument on Polar obtained bulk velocity moments of preexisting upflowing H+, O+, He+, and He++ ions with enough precision and resolution to directly demonstrate, together with computer simulation, that the magnitude and direction of changes in plasma motion during this event follow directly from the changes in the magnetic field configuration as predicted by the equations describing centrifugal acceleration. |
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Bibliography: | ArticleID:1999GL010737 istex:03819D5E0692870C1959E08F5B62C50ADBB24578 ark:/67375/WNG-6KB3M6LV-R ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 |
ISSN: | 0094-8276 1944-8007 |
DOI: | 10.1029/1999GL010737 |