A nonlinear plasma retroreflector for single pulse Compton backscattering

TL;DR

This paper introduces a nonlinear plasma retroreflector that uses a shaped gas target to generate counter-propagating electromagnetic wigglers, enabling efficient single-pulse Compton backscattering of x-rays with tunable spectral properties.

Contribution

It presents a novel plasma-based retroreflector mechanism that enhances Compton scattering by nonlinear interaction with a shaped gas target, optimizing x-ray generation.

Findings

Narrow-band x-rays achieved with moderate intensity pump at quarter-critical surface.

Broadband x-rays produced with high intensity pump near the critical surface.

Theoretical and numerical analysis confirms the nonlinear scattering process.

Abstract

Compton scattered x-rays can be generated using a configuration consisting of a single, ultra-intense laser pulse, and a shaped gas target. The gas target incorporates a hydrodynamically formed density spike, which nonlinearly scatters the incident pump radiation, to produce a counter-propagating electromagnetic wiggler. This self-generated wiggler field Compton scatters from electrons accelerated in the laser wakefield of the pump radiation. The nonlinear scattering mechanism in the density spike is examined theoretically and numerically in order to optimize the Compton scattered radiation. It is found that narrow-band x-rays are produced by moderate intensity pump radiation incident on the quarter-critical surface of the density spike, while high fluence, broadband x-rays are produced by high intensity pump radiation reflected near the critical surface.