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Structure and evolution of the large scale solar and heliospheric magnetic fieldsStructure and evolution of large scale photospheric and coronal magnetic fields in the interval 1976-1983 were studied using observations from the Stanford Solar Observatory and a potential field model. The solar wind in the heliosphere is organized into large regions in which the magnetic field has a componenet either toward or away from the sun. The model predicts the location of the current sheet separating these regions. Near solar minimum, in 1976, the current sheet lay within a few degrees of the solar equator having two extensions north and south of the equator. Soon after minimum the latitudinal extent began to increase. The sheet reached to at least 50 deg from 1978 through 1983. The complex structure near maximum occasionally included multiple current sheets. Large scale structures persist for up to two years during the entire interval. To minimize errors in determining the structure of the heliospheric field particular attention was paid to decreasing the distorting effects of rapid field evolution, finding the optimum source surface radius, determining the correction to the sun's polar field, and handling missing data. The predicted structure agrees with direct interplanetary field measurements taken near the ecliptic and with coronameter and interplanetary scintillation measurements which infer the three dimensional interplanetary magnetic structure. During most of the solar cycle the heliospheric field cannot be adequately described as a dipole.
Document ID
19850002589
Document Type
Thesis/Dissertation
Authors
Hoeksema, J. T. (Stanford Univ. CA, United States)
Date Acquired
September 5, 2013
Publication Date
April 1, 1984
Subject Category
SOLAR PHYSICS
Report/Patent Number
AD-A144990
NASA-CR-175268
NAS 1.26:175268
SU-CSSA-ASTRO-84-07
Funding Number(s)
CONTRACT_GRANT: NAS5-24420
CONTRACT_GRANT: NGR-05-020-599
CONTRACT_GRANT: NSF ATM-77-20580
CONTRACT_GRANT: N00014-76-C-0207
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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