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Robustness optimization for compact free-electron laser driven by laser wakefield accelerators

Hai Jiang1,2, Ke Feng2,*, Runshu Hu2,3, Qiwen Zhan1,†, Wentao Wang2,‡, and Ruxin Li2,3,4

  • *Contact author: fengke@siom.ac.cn
  • †Contact author: qwzhan@usst.edu.cn
  • ‡Contact author: wwt1980@siom.ac.cn
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Phys. Rev. Research 8, 013204 – Published 23 February, 2026

DOI: https://doi.org/10.1103/2mn1-6tb4

Abstract

Despite the successful demonstration of compact free-electron lasers (FELs) driven by laser wakefield accelerators (LWFAs), the inherent shot-to-shot fluctuations in LWFAs, including both laser and plasma instabilities, remain a primary obstacle to realizing LWFA-driven FELs with robust operation. Here, we present a conceptual design for LWFA-driven FELs with sufficient tolerance against shot-to-shot fluctuations using the covariance matrix adaptation evolution strategy. Start-to-end simulations demonstrated that this systematic optimization resulted in a significant improvement in the robustness of FELs. With the optimized configurations, the radiation energy can be maintained above 1µJ at a wavelength of approximately 25 nm, even when accounting for twice the root-mean-square ranges of these instabilities. This proposed scheme represents a substantial advancement in the development of compact LWFA-driven FEL systems, enabling robust operation and paving the way for the realization of reliable and widely accessible sources.

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Phys. Rev. Research 8, 013204– Published 23 February, 2026
  • Received 6 March 2025
  • Accepted 2 February 2026
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