Beam-Driven Systems, Plasma Wakefield Acceleration

TL;DR

This paper reviews plasma wakefield acceleration driven by beam systems, focusing on different bunch regimes, self-modulation, filamentation, and experimental observations of the underlying physics.

Contribution

It provides an expanded, intuitive overview of plasma wakefield acceleration driven by bunch trains, including new insights into self-modulation and filamentation effects.

Findings

Self-modulation enables using long bunches for wakefield driving.

Filamentation limits bunch width before transverse disruption.

Experimental results confirm key physical phenomena.

Abstract

We expand on the material that was published in the previous Proceedings of the CERN Accelerator School on Plasma Wakefield Acceleration. The material focused on Plasma Wakefield Acceleration in the short, narrow bunch regime. After a brief introduction, we describe Plasma Wakefield Acceleration driven by a bunch train. We then attempt to give simple and intuitive descriptions of bunch self-modulation, occurring when the bunch is long, and of current filamentation, occurring when the bunch is wide. Self-modulation is a means to use existing bunches carrying large amounts of energy to drive plasma wakefields. Current filamentation instability imposes a limitation on how wide a particle bunch can be before transverse break-up may disrupt the wakefields generation and the acceleration process. As in the previous material, we show sample experimental results that demonstrate that much of the physics at play has been observed experimentally.