Description
We apply Bayesian optimization in combination with fully three-dimensional particle-in-cell simulations to identify the optimal laser and plasma configurations that, for a fixed laser pulse energy, maximize the electron beam cut-off energy in laser wakefield accelerators [1, 2]. We consider a Gaussian laser pulse with matched spot size and amplitude, exploring two regimes: self-guiding in a uniform-density plasma and external guiding through a preformed plasma channel with a matched radius. To enable a quantitative understanding of the simulation outcomes, we develop novel analytical models for predicting the maximum electron energy and the associated acceleration length, incorporating laser diffraction and energy depletion effects. We then examine how the optimized parameters (such as plasma density, pulse duration, laser amplitude, and spot size) along with resulting beam characteristics (such as energy, charge, acceleration distance, and efficiency), scale with laser systems of arbitrary energy. Finally, we interpret our findings in the broader framework of strong-field physics.
[1] P. Valenta, T. Zh. Esirkepov, J. D. Ludwig, S. C. Wilks, and S. V. Bulanov "Bayesian optimization of electron energy from laser wakefield accelerator", arXiv:2501.06069 [physics.plasm-ph] (2025).
[2] P. Valenta and S. V. Bulanov "Optimized scaling for reaching maximum electron energy from laser wakefield accelerator", Proc. SPIE 13534, Laser Acceleration of Electrons, Protons, and Ions VIII, 1353406 (2025).
