Restricted threedimensional stellar wind modelling. I. Polytropic case.
Abstract
A steady, axisymmetric, nondissipative, threedimensional solar wind model is investigated through the use of a perturbation expansion in inverse Rossby numbers (the ratio of the Coriolis to the inertial forces). Numerical results are presented for a polytropic gas, although the solutions far from the sun are independent of this approximation. The meridional magnetic pressure gradient causes mass to be transported away from the equator, creating an apparent sink in the twodimensional continuity equation there. The mass loss in the equatorial plane is estimated to be a 1020 percent effect at 5 AU, growing logarithmically to large values at greater distances. This illustrates that perturbations that are small everywhere may create effects that are competitive with the unperturbed state, indicating that a full nonlinear analysis is needed in these regions. However, this secular growth is so slow that the linearization is probably valid out to the heliosphere.
 Publication:

The Astrophysical Journal
 Pub Date:
 March 1975
 DOI:
 10.1086/153474
 Bibcode:
 1975ApJ...196..837N
 Keywords:

 Astronomical Models;
 Polytropic Processes;
 Solar Wind;
 Stellar Winds;
 Three Dimensional Flow;
 Three Dimensional Models;
 Magnetohydrodynamics;
 Rossby Regimes;
 Secular Variations;
 Astrophysics