THE SURFACE AMPLITUDES AND FREQUENCIES OF P-MODE OSCILLATIONS IN ACTIVE REGIONS

It is well established that the surface amplitudes of solar p-mode osc illations are reduced in regions of magnetic activity. In this paper, we examine the conjecture that this reduction is produced by direct mo dification of the surface values of the p-mode eigenfunctions, rather than changes in the mode energies or alterations in the spectral line formation process. We calculate the oscillation modes of a solar model with a horizontal magnetic held, convection, and radiative diffusion. We find that magnetic fields with strengths characteristic of solar a ctive regions can produce the observed decrease of surface power.