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Magnetic neutral sheets in evolving fields. I - General theory. II - Formation of the solar coronaThe problem of the hydrostatic equilibrium of a large-scale magnetic field embedded in a fluid with infinite electrical conductivity is considered. It is pointed out that a necessary condition for static equilibrium is the invariance of the small-scale pattern in the field along the large-scale direction. A varying topological pattern implies that no fluid pressure distribution exists for which the field is everywhere static. Magnetic neutral sheets form, and dynamical reconnection of the field takes place. It is shown here that the invariance is also a sufficient condition for the existence of a fluid pressure distribution producing static equilibrium. Even in the simplest cases, however, the requirements on the fluid pressure are extreme and, a priori, are unlikely. It is concluded that almost all twisted flux tubes packed together produce dynamical nonequilibrium and dissipation of their twisting. This is the basic effect underlying the long-standing conjecture that the shuffling of the footpoints of the bipolar magnetic fields in the sun is responsible for heating the active corona. Attention is then given to the consequences of this general dynamical dissipation in the magnetic fields that produce the active corona of the sun. The footpoints of the field are continually manipulated by the subphotospheric convection in such a way that the lines of force are continually wrapped and rotated about one another.
Document ID
19830038292
Document Type
Reprint (Version printed in journal)
Authors
Parker, E. N. (Chicago, University Chicago, IL, United States)
Date Acquired
August 11, 2013
Publication Date
January 15, 1983
Publication Information
Publication: Astrophysical Journal
Subject Category
SOLAR PHYSICS
Funding Number(s)
CONTRACT_GRANT: NGL-14-001-001
Distribution Limits
Public
Copyright
Other