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Helicity of Photospheric Magnetic Fields in Solar Cycle 21Recent analyses of photospheric vector magnetic fields observed during solar cycle 22 have indicated a hemispherical selection rule for magnetic helicity with a predominance of negative (positive) helicity in the northern (southern) hemisphere. Using the extensive data base from the Marshall Space Flight Center's solar vector magnetograph, we have begun a study to derive the helicity for active regions observed during solar cycle 21 and confirm the hemispherical helicity rule for a different solar cycle. In this poster paper, we will present our initial results for several active regions observed in 1980 near the peak of cycle 21, as well as results from analyses designed to test quantitatively the methods used in calculating the helicity.
Document ID
19990103150
Acquisition Source
Marshall Space Flight Center
Document Type
Preprint (Draft being sent to journal)
Authors
Hagyard, Mona J.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Pevtsov, Alexei A.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Canfield, Richard C.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Date Acquired
August 19, 2013
Publication Date
January 1, 1998
Subject Category
Solar Physics
Meeting Information
Meeting: Magnetic Helicity
Location: Boulder, CO
Country: United States
Start Date: July 28, 1998
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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