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A seven-month solar cycle observed with the Langmuir probe on Pioneer Venus OrbiterData collected by the Langmuir probe aboard the Pioneer Venus orbiter (PVO) over the years 1979 though 1987 were normalized to remove the long-period 11-year solar maximum to minimum trend and were analyzed for periodicity. Results yield evidence for the existence of an approximately 7-month solar cycle, which was also observed from SME Lyman alpha and 2800-MHz radio flux measurements carried out from an earth-based platform. This coincidence suggests that the cycle is an intrinsic periodicity in the solar output. The cycle has a frequency independent of the orbital frequency of the PVO and is distinct from a 'rotating beacon' cycle whose period depends on the orbital motion of the PVO about the sun. The second most dominant cycle discovered was a 5-month period. Results of an oscillation model of solar periodicity indicate that the 7-month and 5-month cycles are caused by long-lived flux enhancements from nonlinear interactions of global oscillation modes in the sun's convective envelope (r modes) and radiative interior (g modes).
Document ID
19890058230
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Hoegy, W. R.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Wolff, C. L.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
August 14, 2013
Publication Date
July 1, 1989
Publication Information
Publication: Journal of Geophysical Research
Volume: 94
ISSN: 0148-0227
Subject Category
Solar Physics
Accession Number
89A45601
Distribution Limits
Public
Copyright
Other

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