Effect of Applied Magnetic Field on the Exploding Wire Phenomenon-II

Concepts Study for Nanosecond Risetime Multi-megajoule Impulse Power Systems

“…The most direct method is to make the exploding link long so that the electric field is of such values that ionization of the expanding metallic vapor becomes unlikely. A practical limit of electric field for no restrike has been seen to be approximately 61 kV/m for copper wires in air [2], For many applications, the simple lengthening of the exploding link is undesirable. It has been shown that the energy required to explode a link varies directly as the length of the link [3], moreover, the link inductance also varies directly as its length ['+].…”

“…The application of a magnetic field to the exploding link can make possible higher working electric fields, i.e., shorter length for a given voltage. Researchers have shown that a magnetic field oriented axially to an exploding wire will make operation to approximately 68 kV m possible [2], A magnetic field applied transversely to the flow of current in the exploding link will also have a usable effect. In this instance a force exists governed by: Experiments performed with purposely-overstressed exploding copper wires in air field strengths ranging from 140 to 400 kv/m for axial and transverse magnetic field orientations [5] have shown the transverse field to be far more effective than the axial field in producing delay of restrike.…”