Ion Beam Features Produced by Two Plasma Focus Machines Operated With Different Gases

摘要

Ion beams emitted from the low-inductance kJ NX2 plasma focus have been numerically characterized and trends of these beams in various gases have been reported. In this paper, the ion beams from high-inductance kJ plasma focus machines AECS PF2 and INTI operated with various gases are studied. The obtained results show that the beam ions mean energy depends on the gas type and increases with increasing ion mass of the gas. It also indicates a higher ion fluence for H₂ ( (4.4times 10^{20}) ions m (^{mathrm {-2}}) ), and a very small fluence value for Xe ( (0.085times 10^{20}) ions m (^{mathrm {-2}}) ). The ion number reduces from H₂ ( (24times 10^{14}) ) to Xe ( (0.074times 10^{14}) ). The ion current decreases from H₂ (20.5% of the discharge current) to 5.4% for Xe. The beam energy drops from H₂ (0.63% of stored energy (E_{0}) ) to 0.4% for O₂; however, then increases from Ne to the radiatively-collapsed gases Ar, Kr, and Xe. Argon has the highest damage factor ( (77times 10^{10}) Wm (^{mathrm {-2}}) s (^{0.5}) ), while the lightest gases have the lowest (2– (6times 10^{10}) Wm(^{mathrm {-2}}) s (^{0.5}) ). The magnetic field compressing the pinch is higher for the heavier gases. This paper confirms that the trends of ion beam production with various gases in high-inductance machines are the same as the trends in low-inductance machines.