Coherently enhanced radiation reaction effects in laser-vacuum acceleration of electron bunches

Abstract

The effects of coherently enhanced radiation reaction on the motion of subwavelength electron bunches in interaction with intense laser pulses are analyzed. The radiation reaction force behaves as a radiation pressure in the laser beam direction, combined with a viscous force in the perpendicular direction. Due to Coulomb expansion of the electron bunch, coherent radiation reaction effects only occur in the initial stage of the laser-bunch interaction while the bunch is still smaller than the wavelength. It is shown that this initial stage can have observable effects on the trajectory of the bunch. By scaling the system to larger bunch charges, these effects may be increased to such an extent that they can suppress the radial instability normally found in ponderomotive acceleration schemes, thereby enabling the full potential of laser-vacuum electron bunch acceleration to GeV energies.

Classical formulations of the electromagnetic self-force of extended charged bodies

“…Therefore alternative postulates, such as the Abraham model or other non-rigid models [27], may continue to prove their value. What is more, the current state of technology is starting to enable experimental conditions in which the electromagnetic self-force of macroscopic charged systems, such as high-density electron bunches [55] and ultracold plasma bunches [56], becomes significant. It would be interesting to see to what extent the self-force formulations in this paper can model these evidently non-rigid systems.…”

Non-resonant acceleration of charged particles driven by the associated effects of the radiation reaction

“…Making use of expression (7) from Smorenburg et al. (2010) or the proper adaptation of expression (3) from Vranic et al. (2014), we can promptly show that in regimes of low velocities , the energy variation in the electromagnetic (EM) case is given by , respectively, for co- and counter-propagation.…”

“…In contra-propagating higher-energy situations one can approximate the factor in Smorenburg et al. (2010) by for with , and eventually absorb the factor of in a new field amplitude , but now the highly varying factor would alter the functional dependence of the resulting expression (Vranic et al. 2014).…”

“…Acceleration of charged particles by localized packets of high-frequency electromagnetic carrier waves has been the subject of investigation in a number of recent works (Mulser & Bauer 2010; Smorenburg et al. 2010; Ruiz & Dodin 2017; Almansa et al. 2019).…”

“…Acceleration of charged particles by localized packets of high-frequency electromagnetic carrier waves has been the subject of investigation in a number of recent works (Mulser & Bauer 2010;Smorenburg et al 2010;Ruiz & Dodin 2017;Almansa et al 2019). When the carrier's phase velocity is lower than the speed of light, the full mechanism involves an initial ponderomotive step that accelerates low-velocity particles up to the carrier's phase velocity, at which point these particles are resonantly trapped in the wave's troughs and resonantly accelerated to much larger energies than the initial energy (Tajima & Dawson 1979;Shukla et al 1986;Bingham 2003;Esarey, Schroeder & Leemans 2009;Zhang, Khudik & Shvets 2015).…”