Bruce L Freeman

Fundamental studies of a simple helical magnetic flux compression generator

Summary form only given, as follows. The design of a helical flux compression generator, driven by 150 g of high explosives, for basic studies is presented and experimental results are discussed in comparison to numerical simulations. Simulation of the electric current output with the commercial circuit simulator PSPICE shows that this generator conserves the magnetic flux ideally in the low current mode, <30 kA. At current amplitudes in excess of 100 kA heating and melting of the single wound helix wire, AWG 12, limit the current flow. The volume between armature and stator is spectroscopically probed with fiber optics and valuable insight into the state of the shocked and compressed gas is gained. The same fiber optic probes are used to measure the velocity of the armature-stator contact along the generator axis. This contact velocity is largely affected by armature end effects, mainly due to the pressure loss at the detonator end. Both gas temperature and contact velocity have been successfully simulated with LS-DYNA3D, a three dimensional finite element hydrodynamic code. The generators magnetic field structure is briefly discussed and magnetic field probe measurements are presented.

A multidisciplinary university research program on explosive flux compression

A 5-year DoD Multidisciplinary University Research Initiative (MURI) Program devoted to the paper title was initiated on May 1, 1998. The program involves 3 universities with TTU as the lead university. The main responsibility of TTU is flux compression generator diagnostics, the power conditioning systems, and the metallurgical investigation. The actual explosive tests are done at the UMR and TAM University is investigating the conductivity of shocked gases, such as SF/sub 6/, under high Mach numbers. Internationally known consultants are employed to aid in metallurgical analysis and computer simulations. Foreign cooperation has been established with Loughborough University in the UK. This paper describes the basic research program aimed at understanding flux compression generator losses and improving the power conditioning system.