S Kar | Searcharxiv

arXiv2023

Enhanced proton acceleration from near-critical density targets employing intense lasers with mixed polarization

We demonstrate a scheme for enhanced proton acceleration from near-critical-density targets by splitting a laser pulse into a linearly and a circularly polarized laser pulse. The combination of two laser pulses generates a shock wave as well as hole boring effect at the front surface of the target. Protons at the front get combined acceleration from the two acceleration mechanisms. 2D-PIC simulation shows nearly two-fold enhancement in proton energy from this mechanism for a near-critical density target. The acceleration mechanism is also studied with different target density and thickness to ascertain the target parameters over which the acceleration process shows dominant behaviour.

physics.plasm-ph↗

arXiv2015

Selective Deuterium Ion Acceleration Using the Vulcan PW Laser

We report on the successful demonstration of selective acceleration of deuterium ions by target-normal sheath acceleration (TNSA) with a high-energy petawatt laser. TNSA typically produces a multi-species ion beam that originates from the intrinsic hydrocarbon and water vapor contaminants on the target surface. Using the method first developed by Morrison, et al.,$^{1}$ an ion beam with $>$99$\%$ deuterium ions and peak energy 14 MeV/nucleon is produced with a 200 J, 700 fs, $>10^{20} W/cm^{2}$ laser pulse by cryogenically freezing heavy water (D$_{2}$O) vapor onto the rear surface of the target prior to the shot. Within the range of our detectors (0-8.5$^{\circ}$), we find laser-to-deuterium-ion energy conversion efficiency of 4.3$\%$ above 0.7 MeV/nucleon while a conservative estimate of the total beam gives a conversion efficiency of 9.4$\%$.

physics.plasm-ph↗