Journal Article

Towards the optimisation of direct laser acceleration

Arefiev, A V, Froula, D H, Gong, Z, Theobald, W, Davies, A S, Craxton, R S, Nilson, P M, Williams, G J, Batson, T, Weichman, K, Hussein, A E, Ma, Y, Willingale, L, Haberberger, D, Wang, T, Chen, H

2021

Overview

Experimental measurements using the OMEGA EP laser facility demonstrated direct laser acceleration (DLA) of electron beams to (505 ± 75) MeV with (140 ± 30) nC of charge from a low-density plasma target using a 400 J, picosecond duration pulse. Similar trends of electron energy with target density are also observed in self-consistent two-dimensional particle-in-cell simulations. The intensity of the laser pulse is sufficiently large that the electrons are rapidly expelled along the laser pulse propagation axis to form a channel. The dominant acceleration mechanism is confirmed to be DLA and the effect of quasi-static channel fields on energetic electron dynamics is examined. A strong channel magnetic field, self-generated by the accelerated electrons, is found to play a comparable role to the transverse electric channel field in defining the boundary of electron motion.

• Publisher: IOP Publishing
• Subject: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY / Charge density / electron acceleration / Electron beams / Electron energy / electron heating / Electrons / Laser beams / laser plasma accelerators / laser-plasma / Lasers / magnetic field / Optimization / PARTICLE ACCELERATORS / Particle in cell technique / Physics / Physics - Plasma physics / plasma physics / Pulse propagation