Radial compression stage of a plasma focus: Experimental study

Some results about the compression stage of the current sheath dynamics in a small plasma focus are shown. A very small magnetic probe is used to dete ct the interface plasma-magnetic field, while the luminous front is detecte d with a fast photodetector. Results are presented in pure deuterium discha rges; also neutron yield is registered in each shot. It is found that the n eutron yield drop, at low pressure, is correlated with a significant separa tion between both magnetic and luminous fronts, in concordance with previou s results obtained with other experimental methods. In the pressure range o f best neutron yield, a good correlation between neutrons, current sheath s peed and temporal delay between both Fronts, is found.