Energy dissipation in the run-down phase of plasma focus discharge

The energy dissipation processes in the Mather-type plasma focus discharge, especially in the run-down phase of discharge, were studied. In the present paper the mechanism of energy dissipation and influence of the dissipation on production of neutron yield in a 7 kJ Mather-type plasma focus device have been investigated by using two types of cathode electrode, (1) Sixteen copper-bars arranged along the envelope of cylinder (bar cathode) and (2) Tubular cathode. The energy dissipation in the run-down phase was much lower in the bar cathode than in the tubular one and as a result, the neutron yield was higher in the bar cathode. The present results clearly show that under the same conditions, except for the cathode structure, the energy dissipation correlates with the contact area and the plasma density near cathode.