Fast ion generation in the cathode plasma jet of a multipicosecond laser-triggered vacuum discharge

摘要

Ion generation in the cathode plasma jet of a moderate-current ( ∼ 2.3 kA), low-energy ( ≤ 20 J) vacuum spark discharge triggered by ∼ 27 ps, 10 mJ laser pulses is studied using time of flight technique. Fastest ion velocity and velocity corresponding to the peak of the time of flight signals for Al cathode were measured to be ∼ 5.25×108 cm/s (energy of ∼ 143 keV/u) and ∼ 8.1×107 cm/s (energy of ∼ 3.4 keV/u), respectively. Corresponding velocities in the case of ions generated from laser-produced Al plasma (energy of ∼ 550 mJ, intensity of ∼ 1014 W/cm2) were found to be much smaller, viz., ∼ 1.05×108 cm/s (energy of ∼ 5.75 keV/u) and ∼ 2.63×107 cm/s (energy of ∼ 0.36 keV/u), respectively. Study shows efficient acceleration of ions in a current-carrying cathode plasma jet of a small-energy multipicosecond laser-triggered spark discharge as compared with that in a high-energy multipicosecond laser-produced plasma plume. © 2010 American Institute of Physics Article Outline INTRODUCTION EXPERIMENTAL SETUP EXPERIMENTAL RESULTS DISCUSSION CONCLUSIONS