Published: 2001
Total Pages: 5
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High explosive pulsed power (HEPP) techniques can address a wide range of pulsed power needs. The basis for HEPP techniques is the use of high explosives to reduce the inductance of a current-carrying circuit, thus multiplying the current due to magnetic flux conservation. For the past twenty years at Los Alamos, our high energy density physics (HEDP) program has followed a path leading to more sophisticated and higher current (and often power) systems. Twenty years ago, we had the capability of conducting tests at 10, or even 30 MA, with no power conditioning and low inductance loads. The time scale of the experiment was the time it took to compress the flux explosively, and our fastest generator with high current capability was a plate generator. The operating time of the generator is less than 15 [mu]s, and flux loading requires either an additional ≈60 [mu]s or a reduced-efficiency inductive coupling scheme. We could also deliver shortened pulses to select loads by completing our generator circuit, initially, with a relatively high inductance circuit element, then switching in a lower inductance with 2-3 [mu]s left of the generator pulse. Figure 1 shows the results of such a test. The test was conducted in 1974 to investigate our capability to drive plasma z-pinch experiments for the production of soft x-rays, and was a pulsed power success. However, our understanding of vacuum power flow issues was not mature enough at that time to design a functioning plasma z-pinch load. There was a renewed need for such a system in 1980, and at that time we began assembling a complete set of techniques required for success. We first fielded a baseline test using a simplified version of the HEPP system that generated the Figure 1 data. Subsequent tests followed a 'bite size' philosophy. That is, we first designed a complete system for a level of complexity at which we believed success could be achieved. We conducted tests of that system, and once it was working in all respects, we designed the next generation system. The ultimate goal of this process was to develop a source of ≈1 MJ of soft x-rays. The process culminated, after the development of two intermediate level systems, with the development of the Procyon system. This system produced x-ray pulses of up to 1.7 MJ at temperatures up to 97 eV. Following those experiments, our attention turned to powering solid-density z-pinch liners, requiring even higher current systems. At Los Alamos, we developed the Ranchero system for that purpose, and we have collaborated with HEPP experts in Russia to power similar liner loads using disk generator systems. Our Ranchero system includes a module tested at ≈50 MA, that should operate easily at 70-90 MA. We designed Ranchero to allow modules arrayed in parallel to generate currents over 200 MA, and we are confident that we can do experiments now at 50-200 MA in the same way that we could do tests at 10-30 MA with plate generators 20 years ago. We have recently stepped back from our quest for higher energy and power systems to consider what applications we can address using relatively low cost plate generators coupled with advances achieved in our HEDP system development. We will describe relevant HEPP components, and discuss two promising applications.
