Megagauss Fields Produced with Small Explosive Charges

Abstract

A class of “minigenerators” is described that produces megagauss fields in load coils 9.5 mm diam. × 25 mm long. The minigenerators are scaled down versions of conventional strip or bellows generators. They require less than 90 grams of commercial sheet explosive, and thus could be fired in many laboratories using only a modest containment vessel. The initial flux must be supplied inductively, as the metal components are too flimsy to support sufficient direct current feed. Evidence suggests that peak fields are controlled by conductor current density limitations and the energy available in the explosive. Flash X-ray radiographs of the load coil region show that load coil expansion from magnetic forces is small up to the time of peak field but increases dramatically a few microseconds later. A one-dimensional magnetohydrodynamic code with material properties has been used to predict this behavior, and agreement with experiment is good.

Work supported by the U.S. Department of Energy.