Artículo
The Effect of Proton Temperature Anisotropy on the Solar Minimum Corona and Wind
Fecha de publicación:
01/12/2003
Editorial:
IOP Publishing
Revista:
Astrophysical Journal
ISSN:
0004-637X
Idioma:
Inglés
Tipo de recurso:
Artículo publicado
Clasificación temática:
Resumen
A semiempirical, axisymmetric model of the solar minimum corona is developed by solving the equations for conservation of mass and momentum with prescribed anisotropic temperature distributions. In the high-latitude regions, the proton temperature anisotropy is strong and the associated mirror force plays an
important role in driving the fast solar wind; the critical point where the outflow velocity equals the parallel sound speed (v ¼ ck) is reached already at 1.5 R from Sun center. The slow wind arises from a region with open-field lines and weak anisotropy surrounding the equatorial streamer belt. The model parameters were
chosen to reproduce the observed latitudinal extent of the equatorial streamer in the corona and at large distance from the Sun. We find that the magnetic cusp of the closed-field streamer core lies at about 1.95 R . The transition from fast to slow wind is due to a decrease in temperature anisotropy combined with the onmonotonic behavior of the nonradial expansion factor in flow tubes that pass near the streamer cusp. In the slow wind, the plasma is of order unity and the critical point lies at about 5 R , well beyond the magnetic cusp. The predicted outflow velocities are consistent with O5þ Doppler dimming measurements from UVCS/ SOHO. We also find good agreement with polarized brightness ( pB) measurements from LASCO/SOHO and H i Ly images from UVCS/SOHO.
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Articulos(IAFE)
Articulos de INST.DE ASTRONOMIA Y FISICA DEL ESPACIO(I)
Articulos de INST.DE ASTRONOMIA Y FISICA DEL ESPACIO(I)
Citación
Vasquez, Alberto Marcos; van Ballegooijen, Adriaan A.; Raymond, John C.; The Effect of Proton Temperature Anisotropy on the Solar Minimum Corona and Wind; IOP Publishing; Astrophysical Journal; 598; 2; 1-12-2003; 1361-1374
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