Stable particle acceleration in co-axial plasma channels

TL;DR

This paper demonstrates stable, high-efficiency, monoenergetic electron acceleration to 20 GeV in a co-axial plasma channel, overcoming instabilities that limit transformer ratios in plasma accelerators.

Contribution

It introduces a novel co-axial plasma channel design that controls instabilities, enabling high transformer ratios and stable electron acceleration in plasma accelerators.

Findings

Achieved 20 GeV electron acceleration over 4.4 m

Demonstrated a transformer ratio of 10

Attained 40% energy efficiency and 1.8 μm emittance

Abstract

The attainable transformer ratio in plasma accelerators is limited by instabilities. Using three-dimensional particle-in-cell simulations, we demonstrate that these can be controlled using a hollow plasma channel with a co-axial plasma filament. The driver scatters electrons from the filament, and the slow pinch of the ions leads to a strong chirp of the effective betatron frequency, preventing beam breakup. We demonstrate the monoenergetic acceleration of an electron bunch to 20 GeV over 4.4 m, achieving a transformer ratio of 10, an energy efficiency of 40% and an emittance of 1.8 um.