Crunch-in regime - Non-linearly driven hollow-channel plasma

TL;DR

This paper explores the 'crunch-in' regime in hollow-channel plasma wakefields, revealing how electron-ring collapse enhances acceleration fields and enabling potential collider-scale positron acceleration.

Contribution

It introduces the 'crunch-in' regime, detailing its physical mechanisms, scaling laws, and potential for high-energy positron acceleration using theoretical and simulation methods.

Findings

The 'crunch-in' regime involves electron-ring collapse onto the axis.

Scaling laws relate channel radius to beam and plasma parameters.

Potential application for collider-scale positron acceleration.

Abstract

Plasma wakefields driven inside a hollow-channel plasma are significantly different from those driven in a homogeneous plasma. This work investigates the scaling laws of the accelerating and focusing fields in the "crunch-in" regime. This regime is excited due to the collapse of the electron-rings from the channel walls onto the propagation axis of the energy-source, in its wake. This regime is thus the non-linearly driven hollow channel, since the electron-ring displacement is of the order of the channel radius. We present the properties of the coherent structures in the "crunch-in" regime where the channel radius is matched to the beam properties such that channel-edge to on-axis collapse time has a direct correspondence to the energy source intensity. We also investigate the physical mechanisms that underlie the "crunch-in" wakefields by tuning the channel radius. Using a theoretical framework and results from PIC simulations the possible applications of the "crunch-in" regime for acceleration of positron beams with collider-scale parameters is presented.