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Kelvin-Helmholtz instability and the semiannual variation of geomagnetic activity

1970; American Geophysical Union; Volume: 75; Issue: 31 Linguagem: Inglês

10.1029/ja075i031p06073

2156-2202

Bruce R. Boller, Harold L. Stolov,

Geomagnetism and Paleomagnetism Studies

Journal of Geophysical Research (1896-1977)Volume 75, Issue 31 p. 6073-6084 Kelvin-Helmholtz instability and the semiannual variation of geomagnetic activity Bruce R. Boller, Bruce R. BollerSearch for more papers by this authorHarold L. Stolov, Harold L. StolovSearch for more papers by this author Bruce R. Boller, Bruce R. BollerSearch for more papers by this authorHarold L. Stolov, Harold L. StolovSearch for more papers by this author First published: 1 November 1970 https://doi.org/10.1029/JA075i031p06073Citations: 103AboutPDF 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 Kelvin-Helmholtz instability along the flanks of the magnetosphere exhibits a semiannual variation, instability maximums occurring at the equinoxes and instability minimums at the solstices. It is suggested that Kelvin-Helmholtz instabilities, generated at the magnetopause, initiate the modulation of geomagnetic disturbance detected as the semiannual variation of geomagnetic activity. The Kelvin-Helmholtz explanation predicts a universal time variation of geomagnetic disturbance. This prediction is confirmed by several analyses of the geomagnetic activity indices. Since the physical mechanism suggested for the semiannual variation of geomagnetic activity depends on the tilt of the dipole axis, the 'equinoctial' hypothesis is supported. References Akasofu, S.-I., Polar and Magnetospheric Substorms, D. Reidel, Dordrecht, 1968. Anderson, K. A., J. H. Binsack, D. H. 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