Kinetics of the destruction of type I superconductivity by a current

The dynamics of the destruction of type I superconductivity in a wire by an overcritical current are studied. In a first time interval a normal region grows from the surface surrounding a superconducting cylindrical core which contracts until its radius reaches the radius of the intermediate state core according to London's picture of the static state. In a second step the intermediate state is built up between the normal shell and the superconducting core, which finally disappears. The onset of the intermediate state is a consequence of an instability of the interphase boundary.