Effect of the external outer electrode in plasma-focus discharges

The pinching efficiency of a plasma focus operating with an open cathode was studied by reconstructing the temporal evolution of the inductance of the plasma-electrodes system. It was found that the performance as a neuron generator is substantially reduced compared with the same device configured with a surrounding cage-like cathode. In particular, no pinching occurred in 30 shots performed at 1, 2 and 3 mbar without outer electrode. (brief communication)