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10.7-cm solar radio flux and the magnetic complexity of active regionsDuring sunspot cycles 20 and 21, the maximum in smoothed 10.7-cm solar radio flux occurred about 1.5 yr after the maximum smoothed sunspot number, whereas during cycles 18 and 19 no lag was observed. Thus, although 10.7-cm radio flux and Zurich sunspot number are highly correlated, they are not interchangeable, especially near solar maximum. The 10.7-cm flux more closely follows the number of sunspots visible on the solar disk, while the Zurich sunspot number more closely follows the number of sunspot groups. The number of sunspots in an active region is one measure of the complexity of the magnetic structure of the region, and the coincidence in the maxima of radio flux and number of sunspots apparently reflects higher radio emission from active regions of greater magnetic complexity. The presence of a lag between sunspot-number maximum and radio-flux maximum in some cycles but not in others argues that some aspect of the average magnetic complexity near solar maximum must vary from cycle to cycle. A speculative possibility is that the radio-flux lag discriminates between long-period and short-period cycles, being another indicator that the solar cycle switches between long-period and short-period modes.
Document ID
19880036418
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Wilson, Robert M.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Moore, Ronald L.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Rabin, Douglas
(National Solar Observatory Tucson, AZ, United States)
Date Acquired
August 13, 2013
Publication Date
January 1, 1987
Publication Information
Publication: Solar Physics
Volume: 111
Issue: 2, 19
ISSN: 0038-0938
Subject Category
Solar Physics
Accession Number
88A23645
Distribution Limits
Public
Copyright
Other

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