Explosive flux compression generators at LLNL

At Lawrence Livermore National Laboratory we have developed a coupled helical-coaxial FCG device called the Full Function Test (FFT). This device was used to deliver 98 MA of current and 66 MJ of energy to an inductive load. The successful testing of the FFT represented the culmination of an effort to establish a high-energy pulsed power program that would greatly exceed the performance of capacitor bank facilities. Using the modeling, design, and experimental capabilities developed for the FFT, we have developed a new generator, the Mini-G. Based upon a half-scaling of the FFT device, the Mini-G is a coupled helical-coaxial FCG capable of delivering up to 60 MA of current and 8 MJ of energy. We will describe the design of this generator which involved the use of simulation codes as well as innovative pulsed power techniques to obtain a compact, optimized device.

I. Background

In 2004 LLNL began reconstituting its pulsed power program. Because of the energy and current requirements for performing multi-megabar equation of state experiments (tens of mega-joules and up to one hundred mega-amperes of current) it was felt that high explosive pulsed power (HEPP) was the best option. These requirements could be met with a fixed capacitor machine, but that effort would require a significant expenditure of resources and several years of facility building before the first experiments could be performed.