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The Galileo and Pioneer Venus ultraviolet spectrometer experiments - Solar Lyman-alpha latitude variation at solar maximum from interplanetary Lyman-alpha observationsSolar Ly-alpha latitude variation at solar maximum is examined on the basis of interplanetary Ly-alpha observations made during the Galileo and Pioneer Venus UV spectrometer experiments. A comparison is made of the latitude variation of the interplanetary (IP) Ly-alpha signal in 1986 at solar minimum from Pioneer Venus and in 1990 at solar maximum from Galileo. The Galileo EUV spectrometer shows that a large enhancement of the IP Ly-alpha emission occurred over the intervening four years near the solar equator. An IP Ly-alpha model is developed which considers the latitude variation of the solar Ly-alpha flux. The model fit to the data shows a 25-percent decrease of the full disk solar Ly-alpha flux from solar equator to solar pole in 1990. A detailed study of the Galileo IP Ly-alpha observations on day-of-year 190, 193, 197, and 200 in 1990 reveals that large variations occur in response to the 27-d solar variation. Analysis of these data shows that a maximum variation of 20 percent can be expected in the IP Ly-alpha upwind intensity over this 27-d period.
Document ID
19920065514
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Pryor, W. R.
(Colorado, University Boulder, United States)
Ajello, J. M.
(Colorado, University Boulder; JPL, Pasadena, CA, United States)
Barth, C. A.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Hord, C. W.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Stewart, A. I. F.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Simmons, K. E.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Mcclintock, W. E.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Sandel, B. R.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Shemansky, D. E.
(Colorado, University Boulder, United States)
Date Acquired
August 15, 2013
Publication Date
July 20, 1992
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 394
Issue: 1, Ju
ISSN: 0004-637X
Subject Category
Solar Physics
Accession Number
92A48138
Distribution Limits
Public
Copyright
Other

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