Stable bunch trains for plasma wakefield acceleration

TL;DR

This paper demonstrates that stable plasma wakefield acceleration can be achieved using equidistant bunch trains with increasing charge, provided the plasma frequency exceeds the bunch repetition frequency, ensuring all bunches stay in focusing and decelerating phases.

Contribution

It introduces a method for stable bunch train propagation in plasma wakefield acceleration by adjusting charge distribution and plasma frequency conditions.

Findings

Stable wakefield acceleration with equidistant bunch trains is possible.

Bunch charge must increase along the train for stability.

Plasma frequency should be higher than bunch repetition frequency.

Abstract

A train of short charged particle bunches can efficiently drive a strong plasma wakefield over a long propagation distance only if all bunches reside in focusing and decelerating phases of the wakefield. This is shown possible with equidistant bunch trains, but requires the bunch charge to increase along the train and the plasma frequency to be higher than the bunch repetition frequency.