Explosively formed fuse opening switches for multi-joule applications

摘要

High explosive pulsed power (HEPP) systems are capable of generating very high energies in magnetic fields. Such stored energy is usually developed on time scales of a few tens or hundreds of microseconds. Many applications require shorter pulses and opening switches provide one way to use the large energy available for faster applications. With current flowing in an inductive circuit, introducing resistance produces voltage that can be used to drive current into a load. For an opening switch with a fast rising resistance, the load current rise time is determined by the R/L time constant of the circuit. A significant fraction of the circuit energy must be dissipated in the process, and in applications where very large energies must be dealt with only a few types of switches can be used. Experiments with high explosive driven opening switches have produced a few switches that can carry tens of MA current, and open on the time scale of one or a few (mu)s. (sup 1) We have specialized in a type of switch that we call an explosively formed fuse (EFF) switch at levels of (approximately)3 TW for 2(mu)s has become routine, and we will describe its characteristics and give data from a number of tests.