Coriolis force corrections to g-mode spectrum in 1D MHD model

Abstract

The corrections to g-mode frequencies caused by the presence of a central magnetic field and rotation of the Sun are calculated. The calculations are carried out in the simple one dimensional magnetohydrodynamical model using the approximations which allow one to find the purely analytical spectra of magneto-gravity waves beyond the scope of the JWKB approximation and avoid in a small background magnetic field the appearance of the cusp resonance which locks a wave within the radiative zone. These analytic results are compared with the satellite observations of the g-mode frequency shifts which are of the order one per cent as given in the GOLF experiment at the SoHO board. The main contribution turns out to be the magnetic frequency shift in the strong magnetic field which obeys the used approximations. In particular, the fixed magnetic field strength 700 KG results in the mentioned value of the frequency shift for the g-mode of the radial order n=-10. The rotational shift due to the Coriolis force appears to be small and does not exceed a fracton of per cent, \alpha_\Omega < 0.003.Comment: RevTeX4, 9 pages, 4 eps figures; accepted for publication in Astronomy Reports (Astronomicheskii Zhurnal