Pinch dynamics deduced from terminal current and voltage measurements in a Dense Plasma Focus

Terminal measurements of current and voltage in a dense plasma focus (DPF) are used with a circuit model to deduce the dynamical evolution of the plasma inductance. This inductance in turn gives the dynamical impedance and hence the peak voltage at the pinch, which is found to be $\sim $50kV or higher, for a $\sim $10kV bank voltage. Measurements are described of pinches in a 130kA and a 300kA DPF, with various gases. The dynamical inductance also measures the evolution of the radius of the current carrying region of the imploding pinch. The high pinch voltages and small pinch radii shed light on the neutron production mechanism in such DPFs.