Generation of topologically complex three-dimensional electron beams in a plasma photocathode

TL;DR

This paper demonstrates how laser-triggered ionization injection using Laguerre-Gaussian modes can produce complex three-dimensional electron beams with topological structures in plasma accelerators, verified through theory and simulations.

Contribution

It introduces a novel method of generating 3D topologically complex electron beams using structured laser pulses in plasma wakefield acceleration.

Findings

Generation of exotic 3D electron distributions verified by simulations.

Phase space encoding leads to complex spatiotemporal structures.

Potential for novel beam-plasma interactions and coherent radiation with OAM.

Abstract

Laser-triggered ionization injection is a promising way of generating controllable high-quality electrons in plasma-based acceleration. We show that ionization injection of electrons into a fully nonlinear plasma wave wake using a laser pulse comprising of one or more Laguerre-Gaussian modes with combinations of spin and orbital angular momentum can generate exotic three-dimensional (3D) spatial distributions of high-quality relativistic electrons. The phase dependent residual momenta and initial positions of the ionized electrons are encoded into their final phase space distributions, leading to complex spatiotemporal structures. The structures are formed as a result of the transverse (betatron) and longitudinal (phase slippage and energy gain) dynamics of the electrons in the wake immediately after the electrons are injected. Theoretical analysis and 3D simulations verify this mapping process leads to the generation of these complex topological beams. These beams may trigger novel beam-plasma interactions as well as produce coherent radiation with orbital angular momentum when sent through a resonant undulator.