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Inversion studies of magnetic cloud structure at 0.7 AU: Solar cycle variation
Author(s) -
Mulligan T.,
Russell C. T.,
Elliott D.,
Gosling J. T.,
Luhmann J. G.
Publication year - 2001
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2000gl012016
Subject(s) - magnetic cloud , physics , rope , venus , solar cycle , magnetic field , heliospheric current sheet , solar cycle 23 , heliosphere , magnetic flux , coronal mass ejection , astrophysics , geophysics , solar wind , astrobiology , structural engineering , quantum mechanics , engineering
Pioneer Venus observations from 1979–1988 have revealed the solar cycle evolution of magnetic clouds in the inner heliosphere. Non‐force‐free magnetic rope models, fit to 44 magnetic clouds, allow us to determine the structures of these clouds and compare their properties with potential field maps of their solar source regions. The leading magnetic polarity in these clouds is correlated with the polarity of the sun's global field. The axis of symmetry of the clouds varies with the inclination of the magnetic streamer belt. At 0.72 AU, the median radius of a magnetic flux rope is 0.10 AU. The median rope contains 11 TWb and carries 0.5 GAmps of parallel electric current. The occurrence frequency of different handedness of the ropes is equally left and right throughout the solar cycle and shows no correlation with other modeled parameters.