Problem of sunspot dissipation

A brief survey of the problem and criticism of the known model (Meyer F. et. al.) are given. The number of the necessary conditions which are to be satisfied by the modern theory of the slow decay of sunspots is formulated. The basic idea is to admit some rational distribution of the magnetic field in the sunspot and in the nearby photosphere. This distribution will contain some unknown time-dependent functions, which should be defined (in particular, these functions are the spot radius and the field intensity in the spot center) after the substitution of the magnetic field into the diffusion equation, its integration and the application of the natural electromagnetic boundary conditions (both at infinity and at the spot-photosphere boundary). In particular, the time dependence of the sunspot area