Analytical model for the uncorrelated emittance evolution of externally injected beams in plasma-based accelerators

TL;DR

This paper develops an analytical model to predict the uncorrelated emittance evolution of externally injected beams in plasma accelerators, validated against simulations and semi-analytic methods, enhancing understanding of beam dynamics.

Contribution

It introduces a novel analytical formalism for beam emittance evolution in plasma accelerators, applicable to complex scenarios with energy gain and validated against simulations.

Findings

Excellent agreement between analytical model, SANA, and PIC results.

Model accurately predicts emittance evolution in different plasma accelerator scenarios.

Provides a reliable tool for designing and optimizing plasma-based beam acceleration.

Abstract

This article introduces an analytical formalism for the calculation of the evolution of beam moments and the transverse emittance for beams which are externally injected into plasma wakefield accelerators. This formalism is then applied to two scenarios with increasing complexity - a single beam slice without energy gain and a single beam slice with energy gain, both propagating at a fixed co-moving position behind the driver. The obtained results are then compared to particle-in-cell (PIC) simulations as well as results obtained using an semi-analytic numerical approach (SANA). We find excellent agreement between results from the analytical model and from SANA and PIC.