Emittance preservation in advanced accelerators

TL;DR

This paper reviews the challenges and sources of emittance growth in advanced accelerators, emphasizing the importance of preserving beam quality for applications like free-electron lasers and colliders.

Contribution

It provides a comprehensive overview of emittance preservation challenges and identifies specific sources of emittance growth in various advanced accelerator schemes.

Findings

Space charge and wakefield instabilities cause emittance growth.

Plasma accelerators face additional issues like mismatching and ion motion.

Effective emittance preservation is critical for future accelerator applications.

Abstract

Emittance is a beam quality that is vital for many future applications of advanced accelerators, such as compact free-electron lasers and linear colliders. In this paper, we review the challenges of preserving the transverse emittance during acceleration, both inside and outside accelerator stages. Sources of emittance growth range from space charge and instabilities caused by transverse wakefields, which can occur in any advanced accelerator scheme regardless of medium or driver type, to sources more specific to plasma accelerators, such as mismatching, misalignment, ion motion, Coulomb scattering, chromaticity between stages, and more.