The plasma focus current in the compression phase

Using small magnetic probes, which were decoupled from the ground potential, the plasma focus current was measured. Only some-pressure dependent-fraction of the total current in the device flows at the focus region. The correlation between this current and the neutron yield can be described as Y approximately I 4 . The occurrence of m=0 instabilities in the focus plasma appears in the probe signal and is also correlated to the neutron yield. A comparison between MHD-calculations and the observed field structures is presented.