Component design, development, and testing of an inductive voltage adder (IVA) system for Jupiter
Jupiter is a proposed 15-20 MJ laboratory X-ray source. It would store /spl sim/100 MJ in the Marx generators and deliver /spl sim/500 TW to drive high power z-pinch implosions. The pulsed power requirements for Jupiter were evaluated by a national review panel which concluded that the modular IVA technology as used in HERMES III is capable of meeting these requirements. Modularity of construction permits design verification with less than a full size system and offers the flexibility to meet changing requirements. A program to validate this approach at the required power levels has begun with the construction and testing of components that will comprise a full scale IVA generator module. The IVA module will provide a nominal 10 MV, 1.8 MA, 100 ns FWHM output pulse and will consist of four submodules. Each submodule is composed of a Marx generator, two intermediate energy storage capacitors (ISCs) four pulse forming lines (PFLs), one voltage adder cavity (VAC), plus other associated switches and hardware. A conceptual design for this IVA module has been completed. Initial designs for the ISC, PFL, and their gas switches are also complete and hardware has been procured. Testing of these components is underway at Sandia National Laboratories. Discussions of these designs and results of tests are presented in this paper.
Double-Bounce Switching
Abstract : Double-bounce switching is a technique for exploiting traveling waves in a transmission-line-type pulse forming system to reduce voltage requirements on pulse forming line (PFL) output switches. If a simple PFL (a de charged ideal transmission line with characteristic impedance Z) is switched into a matched load, then peak output power is v2/4Z, where V is output switch voltage. If the PFL is pulse-charged by another transmission line, and if geometries, circuit parameters, and switch points are chosen properly, then the PFL can inject a power much larger than v2/4Z into a matched load. This is the principle of double-bounce switching (so called because it exploits a doubly reflected charging wave in the PFL). Data from EAGLE experiments are presented which demonstrate that the technique works in a real geometry.
Testing of the inductive cores for Hermes III
This paper describes the testing of magnetic cores for the twenty inductively isolated cavities in Hermes III. In this accelerator, the 1.1-MV, 220-kA outputs from four pulse-forming modules will be added in parallel in each of the twenty cavities. The 1-MV, 800-kA summed pulses are fed through the cavities and added by a Magnetically Insulated Transmission Line (MITL) to produce a 20-MV, 800-kA output pulse. Cores from two manufacturers were procured for testing. Each set of cores was specified to have a 0.064 volt . second product to isolate a 1-MV, 40-ns FWHM pulse. The critical properties of these preannealed, Metglas-alloy 2605C0 cores are their B-H loop characteristics and high-voltage insulation capabilities. The B-H loops measured at 60 Hz, 33 kHz, and with a 60-ns pulse indicate a 3.4-T swing. High-voltage life testing was done with a 250-kV, 60-ns pulser. The cores from both manufacturers were pulsed at the Hermes-III design voltage level for greater than 5000 pulses without failures.