NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
A new solar cycle model including meridional circulationA kinematic model is presented for the solar cycle which includes not only the transport of magnetic flux by supergranular diffusion and a poleward bulk flow at the sun's surface, but also the effects of turbulent diffusion and an equatorward 'return flow' beneath the surface. As in the earlier models of Babcock and Leighton, the rotational shearing of a subsurface poloidal field generates toroidal flux that erupts at the surface in the form of bipolar magnetic regions. However, such eruptions do not result in any net loss of toroidal flux from the sun (as assumed by Babcock and Leighton); instead, the large-scale toroidal field is destroyed both by 'unwinding' as the local poloidal field reverses its polarity, and by diffusion as the toroidal flux is transported equatorward by the subsurface flow and merged with its opposite hemisphere counterpart. The inclusion of meridional circulation allows stable oscillations of the magnetic field, accompanied by the equatorward progression of flux eruptions, to be achieved even in the absence of a radial gradient in the angular velocity. An illustrative case in which a subsurface flow speed of order 1 m/s and subsurface diffusion rate of order 10 sq km/s yield 22-yr oscillations in qualitative agreement with observations.
Document ID
19920033894
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Wang, Y.-M.
(Hulburt (E. O.) Center for Space Research Washington, DC, United States)
Sheeley, N. R., Jr.
(Hulburt (E. O.) Center for Space Research Washington, DC, United States)
Nash, A. G.
(U.S. Navy, E.O. Hulburt Center for Space Research, Washington DC, United States)
Date Acquired
August 15, 2013
Publication Date
December 10, 1991
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 383
ISSN: 0004-637X
Subject Category
Astrophysics
Accession Number
92A16518
Funding Number(s)
CONTRACT_GRANT: DPR-W-14429
Distribution Limits
Public
Copyright
Other

Available Downloads

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