Enhanced betatron-radiation energy using two collinear laser pulses

TL;DR

This paper proposes a double-pulse laser scheme in wakefield accelerators that significantly enhances betatron radiation energy, verified through simulations, offering a novel approach for more efficient high-energy photon sources.

Contribution

It introduces a new self-injection method using two matched laser pulses, achieving up to three times higher betatron radiation energy compared to single-pulse schemes.

Findings

Betatron radiation energy can be tripled with double pulses.

A new optimal bubble size condition is derived and validated.

Double-pulse scheme improves self-injection efficiency.

Abstract

A new self-injection scheme is proposed for the laser wakefield accelerator in the nonlinear (cavity) regime using a pair of matched, copropagating laser pulses which yields a pC electron bunch. By tuning their relative delay and intensity, the subsequent betatron radiation energy can be considerably $(\times 3)$ enhanced compared to the single pulse scheme for the same total energy. A new condition for the optimal bubble size is derived and verified by particle-in-cell simulations, demonstrating the advantages of the double-pulse scheme for self-injection.