Capabilities of the Reconfigured Cobra Accelerator

The COBRA accelerator at Cornell University has been reconfigured for use with wire arrays. Design goals included 1 MA peak current with a variable zero to peak current rise-time of as little as 100 ns. COBRA is now driven by two Marx generators, each of which feeds a parallel-plate water capacitor. These capacitors are switched into four parallel pulse-forming lines via self-breaking gas switches. Each pulse-forming line is switched into a vacuum adder via a laser-triggered gas switch that can be independently triggered to provide different pulse shapes to a wire array Z-pinch load. A stainless steel, magnetically insulated current convolute similar to that of the Z-Machine at Sandia National Laboratories connects the output switches to the load. A typical load consists of a 4-8 wire cylindrical array with a diameter of 1.6 cm and a height of 2 cm. To date the refurbished COBRA has over 300 shots. These shots have been used for various reasons including machine diagnostic calibration, laser-triggered switch timing and self breaking switch adjustments as well as experiments with cylindrical wire array and high current X-pinch loads.