ON THE THEORY OF EQUILIBRIUM SUNSPOTS

An axially-symmetric sunspot model is considered. The equilibrium of t he sunspot in the gravity field is supported by magnetohydrodynamic fo rces. The necessary magnetic field is created by azimuthal currents fl owing iniside a limited volume located below the photosphere surface. The sunspot is a depression of the photosphere boundary (Wilson effect ); the temperature distribution at the boundary has a minimum al the c entre of the depression where the magnetic field is maximum. Formulae are derived which relate the temperature distribution and the depressi on profile shape with the magnetic field distribution; the formulae qu alitatively fit the observational data. The presentation of the sunspo t theory is prefaced with a consideration in the first part of the wor k of a simplified model of constitution of <<quiescen>> atmospheres of stars and planets; this model is characterized by two parameters: tem perature gradient and the effective surface temperature. In the second part, cylindrical and spherical models of subphotospheric current reg ions, responsible for great intensities of sunspot magnetic fields, is considered.