Batch Bayesian optimization of attosecond betatron pulses from laser wakefield acceleration

TL;DR

This paper employs numerical simulations and batch Bayesian optimization to enhance attosecond betatron radiation from laser wakefield acceleration, achieving over tenfold increase in on-axis power by optimizing plasma density profiles.

Contribution

It introduces a novel optimization approach combining simulations and Bayesian methods to improve attosecond betatron pulse generation in laser wakefield acceleration.

Findings

Over tenfold increase in on-axis power achieved.

Identification of plasma density spike as a key trigger.

Efficient multi-parameter exploration enabled.

Abstract

Laser wakefield acceleration can generate a femtosecond-scale broadband X-ray betatron radiation pulse from electrons accelerated by an intense laser pulse in a plasma. The micrometer-scale of the source makes wakefield betatron radiation well-suited for advanced imaging techniques, including diffraction and phase-contrast imaging. Recent progress in laser technology can expand these capabilities into the attosecond regime, where the practical applications would significantly benefit from the increased energy contained within the pulse. Here we use numerical simulations combined with batch Bayesian optimization to enhance the radiation produced by an attosecond betatron source. The method enables an efficient exploration of a multi-parameter space and identifies a regime in which a plasma density spike triggers the generation of a high-charge electron beam. This results in an improvement of more than one order of magnitude in the on-axis time-averaged power within the central time containing half of the radiated energy, compared to the reference case without the density spike.