Nonlinear wakefields and electron injection in cluster plasma

TL;DR

This paper investigates how non-homogeneous cluster plasmas influence nonlinear wakefield formation and electron self-injection, revealing mechanisms for enhanced beam charge and implications for advanced particle acceleration.

Contribution

It provides the first detailed PIC simulation study of self-injection in cluster plasmas, highlighting how cluster parameters affect electron trapping and beam properties.

Findings

Cluster plasmas enable efficient electron trapping.

Electron beam charge and energy are tunable via cluster parameters.

Clusters impact laser propagation and wakefield dynamics.

Abstract

Laser and beam driven wakefields promise orders of magnitude increases in electric field gradients for particle accelerators for future applications. Key areas to explore include the emittance properties of the generated beams and overcoming the dephasing limit in the plasma. In this paper, the first in-depth study of the self-injection mechanism into wakefield structures from non-homogeneous cluster plasmas is provided using high-resolution two dimensional particle-in-cell simulations. The clusters which are typical structures caused by ejection of gases from a high-pressure gas jet have a diameter much smaller than the laser wavelength. Conclusive evidence is provided for the underlying mechanism that leads to particle trapping, comparing uniform and cluster plasma cases. The accelerated electron beam properties are found to be tunable by changing the cluster parameters. The mechanism explains enhanced beam charge paired with large transverse momentum and energy which has implications for the betatron x-ray flux. Finally, the impact of clusters on the high-power laser propagation behavior is discussed.