Magnetic flux transfer associated with expansions and contractions of the dayside magnetosphere

Journal Article · Tue Aug 01 04:00:00 EDT 1978 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA083iA08p03831· OSTI ID:6657456

Holzer, R E; Slavin, J A

An empirical magnetopause model is developed by using Ogo 5 magnetometer data, solar wind data from three satellites, and auroral zone magnetic indices. By employing this model it is found that the average displacements of the dayside magnetopause due to changes in solar wind dynamic pressure p/sub sw/ are comparable with, but greater than, the average displacements associated with the transfer of magnetic flux between the nose and the tail of the magnetosphere. After correcting for changes in p/sub sw,/ multiple encounters of the magnetopause occurring over distances of > or =0.5 R/sub e/ on inbound or outbound legs of the satellite orbit are termed contraction or expansion events, respectively. Events occurring during periods of significant ring current, as judged by the Dst index, are excluded from the study. The remaining 24 expansion and contraction events are attributed to net changes ..delta..Phi in the total magnetic flux present in the dayside magnetosphere. The model dependence of the results is discussed, and for the events observed it is found that 2 x 10/sup 15/<..delta..Phi< 2 x 10/sup 16/Mx. For the expansion events, ..delta..Phi shows a positive correlation with the time integral of the auroral zone magnetic index AL over the temporal extent of the observation. A similar correlation between the net flux losses during contraction events with the southward component of the IMF flux impinging on the magnetosphere is complicated by flux returning from the tail during the erosion process. Displacements associated with net flux transfers were observed in all regions of the dayside magnetopause accessible to the satellite, a finding suggesting that the entire dayside magnetosphere is affected by the flux transfer process. The bearing of these results on magnetic reconnection in the earth's magnetosphere is briefly discussed.

• Research Organization: Institute of Geophysics and Planetary Physics, University of California, Los Angeles, California 90024
• OSTI ID: 6657456
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 83:A8; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640203* -- Atmospheric Physics-- Magnetospheric Phenomena-- (-1987)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AURORAL ZONES
CURRENTS
ELECTRIC CURRENTS
INTERPLANETARY MAGNETIC FIELDS
MAGNETIC FIELDS
MAGNETIC FLUX
MAGNETOPAUSE
MAGNETOTAIL
OGO SATELLITES
RING CURRENTS
SATELLITES
SOLAR ACTIVITY
SOLAR WIND