Dephasingless laser wakefield acceleration in the bubble regime

TL;DR

This paper demonstrates a novel laser pulse shaping technique enabling dephasingless electron acceleration in laser wakefield accelerators, significantly increasing achievable energies and improving beam quality.

Contribution

It introduces a space-time structured laser pulse for stable, long-distance electron acceleration in the bubble regime, overcoming dephasing limitations.

Findings

Achieved 2.1 GeV electron energy over 20 dephasing lengths in simulations.

Proposed a laser pulse design that could reach 125 GeV in a single stage.

Enhanced beam stability and quality through pulse shaping techniques.

Abstract

Laser wakefield accelerators (LWFAs) have electric fields that are orders of magnitude larger than those of conventional accelerators, promising an attractive, small-scale alternative for next-generation light sources and lepton colliders. The maximum energy gain in a single-stage LWFA is limited by dephasing, which occurs when the trapped particles outrun the accelerating phase of the wakefield. Here, we demonstrate that a single space-time structured laser pulse can be used for ionization injection and electron acceleration over many dephasing lengths in the bubble regime. Simulations of a dephasingless laser wakefield accelerator driven by a 6.2-J laser pulse show 25 pC of injected charge accelerated over 20 dephasing lengths (1.3 cm) to a maximum energy of 2.1 GeV. The space-time structured laser pulse features an ultrashort, programmable-trajectory focus. Accelerating the focus, reducing the focused spot-size variation, and mitigating unwanted self-focusing stabilize the electron acceleration, which improves beam quality and leads to projected energy gains of 125 GeV in a single, sub-meter stage driven by a 500-J pulse.