The Investigation of Pre-ionization Effect on the Improvement of Pinch Quality and Increased Hard X-ray Radiation in a Dense Plasma Focus (DPF) Device

Abstract

This study delves into the impact of the pre-ionization technique, facilitated by an optimal shunt resistor, on a DPF device operating with deuterium gas. The investigation unveils enhancements in critical parameters within the plasma column environment during the pinch phase, specifically the total and plasmoid hard x-ray yields. Employing a combination of time-resolved detectors, such as plastic scintillator and magnetic probe arrays, alongside time-integrated detectors like pinhole camera, and just by using this technique, the research illustrated an augmented plasma sheath velocity during the axial phase. Notably and other than the enhancement of hard x-ray yield, the optimal pressure of DPF device experienced an upward shift to higher working points, accompanied by a reduction in deviation from the optimum point (52.7% and 66.6% for total and plasmoid hard x-rays respectively). This, in turn, bolstered the Lawson criterion, impacting both particle density and temperature in the plasma column. A nuanced examination further discerned that, while the pre-ionization technique amplified the intensities of total and plasmoid hard x-rays, it maintained a consistent contribution to the emitted hard x-ray intensity from the device, refraining from establishing clear superiority between these two kinds of hard x-rays, with or without using the shunt resistor.