Effects of simulation dimensionality on laser-driven electron acceleration and photon emission in hollow micro-channel targets

TL;DR

This study compares 2D and 3D simulations of laser-driven electron acceleration in hollow micro-channel targets, highlighting how dimensionality affects electron energy, photon emission, and the importance of 3D modeling for accurate predictions.

Contribution

It demonstrates the significant influence of simulation dimensionality on electron acceleration and photon emission, emphasizing the necessity of 3D simulations for precise experimental predictions.

Findings

3D simulations show earlier electron acceleration termination due to higher phase velocity.

2D simulations produce more energetic electrons and less diverged photon beams.

Qualitative features are similar, but quantitative accuracy requires 3D modeling.

Abstract

Using two-dimensional (2D) and three-dimensional (3D) kinetic simulations, we examine the impact of simulation dimensionality on the laser-driven electron acceleration and the emission of collimated $\gamma$-ray beams from hollow micro-channel targets. We demonstrate that the dimensionality of the simulations considerably influences the results of electron acceleration and photon generation owing to the variation of laser phase velocity in different geometries. In a 3D simulation with a cylindrical geometry, the acceleration process of electrons terminates early due to the higher phase velocity of the propagating laser fields; in contrast, 2D simulations with planar geometry tend to have prolonged electron acceleration and thus produce much more energetic electrons. The photon beam generated in the 3D setup is found to be more diverged accompanied with a lower conversion efficiency. Our work concludes that the 2D simulation can qualitatively reproduce the features in 3D simulation, but for quantitative evaluations and reliable predictions to facilitate experiment designs, 3D modelling is strongly recommended.