Fossil magnetic fields of the sun and stars

Abstract

Using helioseismologically inferred internal rotation given by Dziembowski et al., 1989, in the previous work, we (Hiremath and Gokhale 1995, Hiremath 1995) modelled the steady (fossil) part of the poloidal magnetic field structure as that which isorotates with the sun's internal rotation. In the present study, we use the sun's internal rotation recently obtained by Anita et al., (1998), from the GONG data. The results of the present work are almost similar to our previous work but are much more accurate. It is important to note that it is possible to obtain a high degree of isorotation between an eigen-solution of the diffusion equation and the internal rotation inferred from the latest helioseismic data, by fitting only a few parameters in the eigen-solution. It is found that magnitude of the poloidal magnetic field varies substantially with the radial direction and is nearly independent of latitude. We plan to extend our work to other stars on the main sequence and white dwarfs.