NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Cooling of a sunspotThe question of whether a perturbed photospheric area can grow into a region of reduced temperature resembling a sunspot is investigated by considering whether instabilities exist that can lead to a growing temperature change and corresponding magnetic-field concentration in some region of the photosphere. After showing that Alfven cooling can lead to these instabilities, the effect of a heat sink on the temperature development of a perturbed portion of the photosphere is studied. A simple form of Alfven-wave cooling is postulated, and computations are performed to determine whether growing modes exist for physically relevant boundary conditions. The results indicate that simple inhibition of convection does not give growing modes, but Alfven-wave production can result in cooling that leads to growing field concentration. It is concluded that since growing instabilities can occur with strong enough cooling, it is quite possible that energy loss through Alfven waves gives rise to a self-generating temperature change and sunspot formation.
Document ID
19770055581
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Boruta, N.
(Chicago, University Chicago, Ill., United States)
Date Acquired
August 9, 2013
Publication Date
July 1, 1977
Publication Information
Publication: Astrophysical Journal
Subject Category
Solar Physics
Accession Number
77A38433
Funding Number(s)
CONTRACT_GRANT: NGL-14-001-001
Distribution Limits
Public
Copyright
Other

Available Downloads

There are no available downloads for this record.
No Preview Available