Laser-driven Collisionless Shock Acceleration of Ions from Near-critical plasmas

TL;DR

This paper reviews experimental and simulation results on laser-driven collisionless shock acceleration of ions in near-critical plasmas, achieving high-energy narrow spread ion beams with potential for optimization.

Contribution

It presents new experimental data and numerical simulations demonstrating ion acceleration via electrostatic shocks in near-critical density plasmas, highlighting the need for target density profile control.

Findings

High-energy proton and carbon ion beams with narrow energy spread achieved.

Observation of similar velocities for protons and carbon ions, indicating shock reflection.

Simulations suggest target density profile control is crucial for optimization.

Abstract

This paper overviews experimental and numerical results on acceleration of narrow energy spread ion beams by an electrostatic collisionless shockwave driven by 1 um (Omega EP) and 10 um (UCLA Neptune Laboratory) lasers in near critical density CH and He plasmas, respectively. Shock waves in CH targets produced high-energy 50 MeV protons (energy spread of <30%) and 314 MeV C6+ ions (energy spread of <10%). Observation of acceleration of both protons and carbon ions to similar velocities is consistent with reflection of particles off the moving potential of a shock front. For shocks driven by CO2 laser in a gas jet, 30 MeV peak in He ion spectrum was detected. Particle-in-cell simulations indicate that regardless of the target further control over its density profile is needed for optimization of accelerated ion beams in part of energy spread, yield and maximum kinetic energy.