Boundaries of the plasma-free regime of electroexplosion of a foil

Results of the experimental studies of the commutation characteristics of an electroexplosive breaker upon heating of a copper foil by a current pulse of duration $\tau\approx1$msec are given. The dependences of the electric-field strength and the specific power of the circuit breaker during an electroexplosion of the foil on the specific power of the source $P_s$ are found and it is shown that the transition of the plasma-free regime of electroexplosion of the foil to a plasma regime occurs for $P_s=30-40$GW/g.