VLF emissions associated with enhanced magnetospheric electrons
1977; American Geophysical Union; Volume: 82; Issue: 1 Linguagem: Inglês
10.1029/ja082i001p00135
ISSN2156-2202
Autores Tópico(s)Earthquake Detection and Analysis
ResumoJournal of Geophysical Research (1896-1977)Volume 82, Issue 1 p. 135-146 VLF emissions associated with enhanced magnetospheric electrons Roger R. Anderson, Roger R. AndersonSearch for more papers by this authorKaichi Maeda, Kaichi MaedaSearch for more papers by this author Roger R. Anderson, Roger R. AndersonSearch for more papers by this authorKaichi Maeda, Kaichi MaedaSearch for more papers by this author First published: 1 January 1977 https://doi.org/10.1029/JA082i001p00135Citations: 133AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat Abstract During periods of geomagnetic disturbances, VLF emissions and enhancements of low-energy electrons are simultaneously observed by the equatorial orbiting S³-A (Explorer 45) satellite. These events are characterized by the following features. (1) The VLF emissions occur outside the plasmasphere in the nightside of the magnetosphere. (2) The VLF emissions consist of two frequency regimes, one below the local electron gyrofrequency fg and the other above fg. (3) The VLF emissions below fg are relatively broadband whistler mode waves characteristic of chorus and frequently have a conspicuous band of 'missing emissions' near fg/2. (4) The emissions above fg are electrostatic and typically have components near 3fg/2. Occasionally, higher-frequency components are also observed. (5) The onset of the emissions coincides with abrupt increases outside the plasmasphere (L ≳ 4) in 1- to 10-keV electrons to intensities of the order of 108 el cm−2 s−1 sr−1 keV−1. Less pronounced enhancements sometimes occur for electrons with energies as high as 70 keV. (6) The cessation of the emissions coincides with a drop in the electron intensities to their preenhancement levels, which are of the order of 106 el cm−2 s−1 sr−1 keV−1 or less. This drop in low-energy electron intensities occurs before or when the satellite crosses the plasmapause back into the plasmasphere. These observed features indicate that the VLF emissions are produced by low-energy (1- to 10-keV) electrons which penetrate into the dusk-midnight sector of the magnetosphere from the geomagnetic tail during magnetic storms and substorms and drift eastward outside the plasmasphere. In this paper, events observed during geomagnetically disturbed periods in December 1971 and January 1972 are discussed. 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Citing Literature Volume82, Issue1Space Physics1 January 1977Pages 135-146 ReferencesRelatedInformation
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