Optimal parameters for radiation reaction experiments

Abstract

As new laser facilities are developed with intensities on the scale of 10 22 −10 24 Wcm −2 , it becomes ever more important to understand the effect of strong field quantum electrodynamics processes, such as quantum radiation reaction, which will play a dominant role in laser-plasma interactions at these intensities. Recent all-optical experiments, where GeV electrons from a laser wakefield accelerator encountered a counter-propagating laser pulse with a0 > 10, have produced evidence of radiation reaction, but have not conclusively identified quantum effects nor their most suitable theoretical description. Here we show the number of collisions and the conditions required to accomplish this, based on a simulation campaign of radiation reaction experiments under realistic conditions. We conclude that while the critical energy of the photon spectrum distinguishes classical and quantumcorrected models, a better means of distinguishing the stochastic and deterministic quantum models is the change in the electron energy spread. This is robust against shot-to-shot fluctuations and the necessary laser intensity and electron beam energies are already available. For example, we show that so long as the electron energy spread is below 25%, collisions at a0 = 10 with electron energies of 500 MeV could differentiate between different quantum models in under 30 shots, even with shot to shot variations at the 50% level.

Radiation reaction in electron–beam interactions with high-intensity lasers

“…( 23); to see stochastic effects, we must consider instead the width of the distribution [59,61,62]. Given electron beams with narrower initial energy spectra, it would be possible to identify stochastic effects (or their absence) by correlating the mean and variance of the final electron energy spectra [177].…”

Model-independent inference of laser intensity

“…As the best choice of model depends on the intensity, relaxing the requirement that one must be assumed a priori means that our method provides strong evidence that a particular intensity range has been reached. This is particularly useful for experiments intended to distinguish between radiation reaction models, as this becomes feasible in a reduced number of successful collisions if a 0 can be measured independently [33]. The quantities necessary to use eq.…”

ML-Based Analysis of Particle Distributions in High-Intensity Laser Experiments: Role of Binning Strategy

“…The scheme of the numerical experiment is close to the one used in Ref. [ 16 ]. Initially, the electrons in the bunch have the energy , where is the relativistic Lorentz-factor.…”