Coronal Magnetic - Field Model with Nonspherical Source Surface

Previous global models of coronal magnetic fields have used a geometrical construction based on a spherical source surface because of requirements for computational speed. As a result they have had difficulty accounting for the tendency of full magnetohydrodynamic (MHD) models to predict non-radial...

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Bibliographic Details
Main Authors: Schulz,Michael, Frazier,Edward N, Boucher,Donald J , Jr
Format: Report
Language:English
Subjects:
Alfuen waves
Astrophysics
MAGNETIC DIPOLES
MAGNETIC FIELDS
MAGNETOHYDRODYNAMICS
MATHEMATICAL MODELS
SOLAR CORONA
SOLAR PHYSICS
SOLAR WIND
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Summary:Previous global models of coronal magnetic fields have used a geometrical construction based on a spherical source surface because of requirements for computational speed. As a result they have had difficulty accounting for the tendency of full magnetohydrodynamic (MHD) models to predict non-radial plasma flow out to r about 10 solar radii and the appreciable magnitude, about 3 gamma, of Br (the radial component of B) consistently observed at r about 1 AU. A new modelling technique based on a nonspherical source surface is presented, which is taken to be an isogauss of the underlying potential field generated by currents in or below the photosphere. This modification of the source surface significantly improves the agreement between the geometrical construction and the MHD solution while retaining most of the computational ease provided by a spherical source surface.