NASA Logo, External Link
Facebook icon, External Link to NASA STI page on Facebook Twitter icon, External Link to NASA STI on Twitter YouTube icon, External Link to NASA STI Channel on YouTube RSS icon, External Link to New NASA STI RSS Feed AddThis share icon
 

Record Details

Record 1 of 7351
Observed Helicity of Active Regions in Solar Cycle 21
Offline Availability: Go to Request Form
Author and Affiliation:
Hagyard, M. J.(NASA Marshall Space Flight Center, Huntsville, AL, United States)
Pevtsov, A. A.(NASA Marshall Space Flight Center, Huntsville, AL, United States)
Blehm, Z.(NASA Marshall Space Flight Center, Huntsville, AL, United States)
Smith, J. E.(NASA Marshall Space Flight Center, Huntsville, AL, United States)
Six, Frank [Technical Monitor](NASA Marshall Space Flight Center, Huntsville, AL, United States)
Abstract: We report the results of a study of helicity in solar active regions during the peak of activity in solar cycle 21 from observations with the Marshall Space Flight Center's solar vector magnetograph. Using the force-free parameter alpha as the proxy for helicity, we calculated an average value of alpha for each of 60 active regions from a total of 449 vector magnetograms that were obtained during the period 1980 March to November. The signs of these average values of alpha were correlated with the latitude of the active regions to test the hemispheric rule of helicity that has been proposed for solar magnetic fields: negative helicity predominant in northern latitudes, positive in the southern ones. We have found that of the 60 regions that were observed, 30 obey the hemispheric rule and 30 do not.
Publication Date: Jan 01, 2003
Document ID:
20030063080
(Acquired Aug 07, 2003)
Subject Category: SOLAR PHYSICS
Document Type: Preprint
Financial Sponsor: NASA Marshall Space Flight Center; Huntsville, AL, United States
Organization Source: NASA Marshall Space Flight Center; Huntsville, AL, United States
Description: 1p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: No Copyright
NASA Terms: SOLAR CYCLES; SOLAR ACTIVITY; MAGNETIC STORMS; SOLAR MAGNETIC FIELD; MAGNETIC SIGNATURES; MAGNETOMETERS; ELECTRICAL MEASUREMENT; PATTERN REGISTRATION
› Back to Top
Find Similar Records
NASA Logo, External Link
NASA Official: Gerald Steeman
Site Curator: STI Program
Last Modified: September 08, 2011
Contact Us