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Solar wind variations and geomagnetic storms - A study of individual storms based on high time resolution ISEE 3 dataTwo independent methods are employed to determine the relationship between the parameter epsilon and total energy dissipation rate of the magnetosphere U sub T by selecting disturbed periods from the same data d set used by Baker et al. (1983). Specifically, four storms are examined in detail, since the accuracy of estimating U sub T is significantly improved during disturbed periods. The first method assumes that U sub T = M sub A exp.2- alpha(epsilon) where M sub A is the Alfven Mach number and alpha varies with time. The second method considers a linear, time-invariant dynamic system with epsilon as input and U sub T as output. This means that U sub T = W(asterisk)epsilon where asterisk is the convolution and W is a transfer function characteristic of the system. It is found that alpha values fluctuate mainly between 0 and -0.25. The transfer function analysis indicates that W often resembles a delta-function or a narrow rectangular impulse. Both results give the same implication (namely that U sub T is approximately equal to epsilon) and thus are consistent with the view that the magnetosphere is primarily a directly driven system during disturbed periods.
Document ID
19850036986
Document Type
Reprint (Version printed in journal)
Authors
Akasofu, S.-I. (Alaska Univ. Fairbanks, AK, United States)
Olmsted, C. (Alaska, University Fairbanks, AK, United States)
Smith, E. J. (Alaska Univ. Fairbanks, AK, United States)
Tsurutani, B. (Alaska Univ. Fairbanks, AK, United States)
Okida, R. (California Institute of Technology, Jet Propulsion Laboratory, Pasadena CA, United States)
Baker, D. N. (Los Alamos National Laboratory Los Alamos, NM, United States)
Date Acquired
August 12, 2013
Publication Date
January 1, 1985
Publication Information
Publication: Journal of Geophysical Research
Volume: 90
ISSN: 0148-0227
Subject Category
GEOPHYSICS
Funding Number(s)
CONTRACT_GRANT: NSF ATM-83-12515
CONTRACT_GRANT: NSG-7447
Distribution Limits
Public
Copyright
Other