Single-shot Transverse Wakefield Mapping with a Hollow Electron Beam

TL;DR

This paper presents a novel single-shot method using a hollow electron beam to directly measure transverse wakefields in beam-driven accelerators, aiding in the development of mitigation strategies for beam stability.

Contribution

Introduction of a beam-based single-shot transverse wakefield measurement technique using a hollow electron probe for detailed wakefield mapping.

Findings

Demonstrated the method's effectiveness through start-to-end simulations.

Enabled direct measurement of transverse wakefield structures.

Potential to develop mitigation schemes for beam stability issues.

Abstract

Beam-driven wakefield accelerators are foreseen to enable compact accelerator-based light sources and play a critical role in future linear-collider concepts. This class of wakefield acceleration has been extensively studied over the last four decades with a focus on demonstrating its ability to support high-accelerating gradient and, most recently, enhanced transformer ratios. Yet, the associated detrimental transverse wakefields have not been examined in as many details due to the limited diagnostics available. In this paper, we introduce a beam-based single-shot transverse-wakefield measurement technique. The approach employs a witness ''hollow" electron beam to probe the wakefields generated by a drive bunch. We show how the transverse distortions of the hollow probe provide a direct measurement of the wakefield distribution within the area circumscribed by the probe. The ability to directly measure a full structure of the transverse wakefield could help to develop mitigation schemes and ultimately suppress the adverse beam-break-up instabilities. We discuss a practical implementation of the method and demonstrate its performance with the help of start-to-end simulations.