  It is shown that there are exact solutions of the free Maxwell equations
(FME) in vacuum allowing an existence of stable spherical formations of the
free magnetic field and ring-like formations of the free electric field. It is
detected that a form of these spheres and rings does not change with time in
vacuum. It is shown that these convergent solutions are the result of an
interference of some divergent solutions of FME. One can surmise that these
electromagnetic formations correspond to Kapitsa's hypothesis about
interference origin and a structure of fireball.
