Coupling Effects in Multi-Stage Laser Wake-field Acceleration of Electrons

TL;DR

This paper investigates the coupling effects in multi-stage laser wake-field acceleration, demonstrating stable electron beam generation and efficient injection through experimental characterization and simulations.

Contribution

It provides a detailed analysis of coupling mechanisms in staged laser wake-field acceleration, including experimental validation and simulation comparison.

Findings

Stable, narrow energy band electron beams (<3%) generated.

Effective electron injection via cumulative focusing and the Budker-Bennett effect.

Agreement between experimental results and multidimensional simulations.

Abstract

Staging laser wake-field acceleration is considered as a necessary technique for developing full-optical jitter-free electron accelerators. Splitting of the acceleration length into several technical parts with their lengths smaller than the dephasing length and with independent laser drivers allows generation of stable, reproducible acceleration fields. Temporal and spatial coupling of pre-accelerated electron bunches for their injection in the acceleration phase of a successive laser pulse wake field is the key part of the staging laser-driven acceleration. Here, characterization of the coupling is performed with dense, stable, a narrow energy band <3% and energy selectable electron beams with charges ~1.6 pC and energy ~10 MeV generated from a laser plasma cathode. Cumulative focusing of electron bunches in a low density pre-plasma, exhibiting the Budker- Bennett effect, is shown to result in the efficient injection of electrons even with a long distance between the injector and the booster in the laser pulse wake. Measured characteristics of electron beams modified by the booster wake field agree well with those obtained by multidimensional particle-in-cell simulations.