Explosion instability in the thermal expansion of a thin-walled cylinder in ultra-high magnetic field

Summary form only given, as follows. Thermal expansion of a thin-walled cylinder in fast Joule heating enables one to obtain high wall velocity (up to 10000 m/s) without its evaporation. In strong longitudinal magnetic field the heating by azimuthal current has the decisive role. The process then follows the succeeding line: with the wall velocity increase the induced azimuthal current and Joule heating power grow. This, in its turn, results in the wall acceleration due to its thermal expansion. So, the self-excitation process of the azimuthal current and sharp acceleration of the wall are possible. The calculations described in the report are made in the assumption of constant induction B/sub 0/ at the outer cylinder wall. They show that the process has the character of explosion instability: azimuthal current sharply increases in finite time near certain time instant t/sub 1/: I/sub /spl phi//=[(6h/spl gamma/R/sub 0/)//spl Gamma//sub 0/B/sub 0/](t/sub 1/-t)/sup -2/. The wall velocity follows the same law. This effect is observed for the liquid metal shell in spite of the action of electromagnetic braking forces. It is characteristic that the heating and acceleration of the shell consume the energy of the external field. The wall acceleration is possible also for a solid wall, if induction has the order of 100 T or more.