Laser Wakefield Acceleration Driven by a Discrete Flying Focus

TL;DR

This paper introduces a discrete flying focus technique in laser wakefield acceleration that enables higher energy gains within a single stage, potentially simplifying the development of high-energy lepton colliders.

Contribution

The paper proposes a novel discrete flying focus method to increase energy gain in LWFA, reducing the need for multiple stages and addressing alignment and matching challenges.

Findings

Simulations show 40 GeV energy transfer in a 30-cm stage

A 150 J laser pulse achieves near-constant acceleration over 50 dephasing lengths

Single-stage acceleration reduces complexity compared to multi-stage setups

Abstract

Laser wakefield acceleration (LWFA) may enable the next generation of TeV-scale lepton colliders. Reaching such energies will likely require multiple LWFA stages to overcome limitations on the energy gain achievable in a single stage. The use of stages, however, introduces challenges such as alignment, adiabatic matching between stages, and a lower average accelerating gradient. Here, we propose a discrete flying focus that can deliver higher energy gain in a single stage, thereby reducing the number of stages required for a target energy. A sequence of laser pulses with staggered focal points and delays drives a plasma wave in which an electron beam experiences a near-constant accelerating gradient over distances beyond those attainable with a conventional pulse. Simulations demonstrate that a discrete flying focus with a total energy of 150 J can transfer 40 GeV per electron to a 50-pC beam in a single 30-cm stage, corresponding to 50 dephasing lengths.