Superconducting state stability in current charging into composites.

Numerical and analytical calculations of the current charging process into a round superconducting composite with properties homogenized over its cross-section are presented. A limiting current exists below which the wire remains in the superconducting state and above which the wire is quenched when current charging is stopped; this current is somewhat less than the take-off current. The approximate analytical solution of the problem is defined. The non-isothermality of the wire, its heat capacity, and its thermal and electric conductivities are taken into account in the derived stability criterion.