Comparisons of the activities of UV Cet-type flare stars and of T Tau-type stars with solar activity permits the conclusion that non-sta-tionary processes in the UV Cet-type stars and in the Sun are of an indent ical physical nature but that they differ qualitatively from active events in the T Tau-type stars. The identity of the activity in flare stars and the Sun makes it possible to study successfully stellar activity with the help of known models of various solar events and, on the other hand, to have a more general approach to the physics and evolution of solar activity on the basis of established features of numerous flare stars of different ages and masses. The hypothesis on hydromagnetic activity of the T Tau-type stars is sketched; within this framework, one supposes that the main feature of such stars is an occurrence at every point of the stellar surface, of conditions necessary for the existence of dark spots, i.e. a lowering of the photospheric brightness due to strong local magnetic fields.
Can cellular convection in a rotating spherical shell maintain both global and local magnetic fields?
