High-voltage pulsed-power sources for high-energy experimentation

A high-energy pulsed-power source based on a 30 kJ capacitor bank has recently been developed at Loughborough University. An H-bridge circuit configuration is used, with one pair of the diagonally opposite arms comprising a high-voltage ballast inductor and the other pair an exploding wire array capable of generating voltages up to 250 kV. The two centre points of the H-configuration provide the output to a high-power resistive load, which is coupled through a high-voltage self breakdown spark gap. A resistive load of 80 Ω is provided with a 300 kV impulse with a rise time of about 140 ns and a peak power of about 1 GW. Following the successful testing of the power source under indoor laboratory conditions, a similar transportable source was constructed. This is presently housed in a metal container, with the load fed through a pair of 25 m long high-voltage cables. Due to improvements in the exploding wire arrays arrangement, each now generating about 300 kV, the source is capable of delivering a power of 1.7 GW to a 45 Ω load. The Joule energy deposited of about 3 kJ represents 10% of the energy initially stored in the capacitors. The design of a more powerful transportable source, presently under construction and based on a 400 kJ capacitor bank will also be presented. This source, using an exploding wire array in the primary circuit of a high-voltage transformer, is predicted to be capable of generating in resistive loads an electrical power in excess of 4 GW.