Observation of Plasma Dynamics in Axial and Radial Phase of DPF Device with Varying Gas Pressure

The axial and radial phase plasma dynamics of PF-1000 plasma focus device with respect to filling gas pressure has been studied using 5-phase Lee model code (RADPFV5.15de.xls). The device is fitted into the code using data from standard laboratory experiment. The fitting is completed when the overall current profile generated by the code matched with the experimental current profile. The Pressure is then varied from 1 Torr to 30 Torr. From the data of the numerical experiment, relationship of the plasma sheath speeds in different phases i.e., axial speed ($v _{a}$), radial inward shock speed ($v _{s}$) and piston speed ($v _{p}$) with pressure ($P _{0}$) are evaluated. The correlations are found as follows,\begin{equation*} v _ { a } \approx 19 P _ { 0 } ^ { - 0.4 } , v _ { s } \approx 33 P _ { \theta } ^ { - 0.55 } \text { and } v _ { p } \approx 25 P _ { 0 } ^ { - 0.57 }\end{equation*}These findings are important to design and fabrication of efficient DPF devices as well as to improve experimental procedure.