Fast valve and nozzle for gas-puff operation of dense plasma focus

A simple and reliable valve and nozzle system for a very fast injection of gas has been designed and constructed for its use in gas-puff mode of dense plasma focus experiments. It delivers a very quick rise time: 55 μs. The pressure measured in our setup at a distance of 15 mm from the nozzle output is about 0.285 mbar, with a plenum pressure of 3 bars (absolute). The time between the valve aperture and pressure front arrival is 360 μs. This result comes up as an average of about a hundred measurements. The energy input is 95 J (270 V on a 3000 μF capacitor bank). The typical dimensions of the valve are 52 mm in diameter and 80 mm in length. The entire volume of the valve is, then, very small. The relative low pressure and voltage operation are significant advantages of this development. The performance of the valve satisfactorily fulfills the objectives of gas-puff plasma focus operation