NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Collections About News Help Login
Back to Results
Solar Response to Luminosity VariationsThe connection between solar luminosity and magnetic fields is now well-established. Magnetic fields under the guise of sunspots and faculae enhance or suppress heat transfer through the solar surface, leading to changes in the total solar luminosity. This raises the question of the effect that such surface heat transfer perturbations have on the internal structure of the sun. The problem has been considered previously by Foukal and Spruit. Here, researchers generalize the calculation of Spruit, removing the assumption of a constant heat diffusivity coefficient by treating the full mixing length heat transfer expression. Further, they treat the surface conditions in a simpler manner, and show that the previous conclusions of Foukal and Spruit are unaffected by these modifications. The model shows that following the application of a step function emissivity change: a fraction 1 - D(sub 0) of the luminosity change relaxes away after approx. 50 days. This corresponds to the thermal diffusion time across the convection zone, adjusting to a value in correspondence with the surface change. In other words, the whole convection zone feels the perturbation on this timescale. The remaining fraction relaxes away on a timescale of 10 to the 5th power years, corresponding to the convective layer radiating away enough energy so that it can adjust to its new adiabat. These are the same results arrived at by Spruit and Foukal. For variations of sigma on timescales of 10 to 200 years, then, the only important relaxation is the 50 day one. If the amplitude of this relaxation is small, the luminosity follows the sigma variation.
Document ID
19910003154
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Arendt, S. (Chicago Univ. Chicago, IL, United States)
Date Acquired
September 6, 2013
Publication Date
August 1, 1990
Publication Information
Publication: NASA, Goddard Space Flight Center, Climate Impact of Solar Variability
Subject Category
Solar Physics
Accession Number
91N12467
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

Related Records

There are no records associated with this record.
No Preview Available