Magnetic Probe Measurements in a Filippov-Type PF Facility

A detailed theoretical and experimental description of the function of a magnetic probe, inserted into the discharge chamber of a 90-kJ Filippov-type plasma focus facility, is presented. Using this probe, some experimental measurements of temporal evolution of the current sheath in the radial expansion phase of the PF discharges, have been performed. Among others, we found that, for a given gas, with constant bank voltage, and pressure, the expansion velocity of the current sheath is constant, and as long as the CS has not collided with the cathode, the power of the pinch is independent of this velocity. We also found that in our Filippov-type PF facility, with 16 kV discharge voltage, and a pressure of 0.8 Torr, the expansion velocity of the current sheath is about 1.49 cm/μs for neon, and about 2.90 cm/μs for d2 + 2%kr.