Status Report on the Hydrodynamic Simulations of a Tapered Plasma Lens for Optical Matching at the ILC $e^+$ Source

TL;DR

This paper presents preliminary hydrodynamic simulations of a tapered plasma lens designed for optical matching of positron beams at the ILC, aiming to improve beam capture efficiency using plasma technology.

Contribution

It provides initial hydrodynamic simulation results supporting the development of a tapered plasma lens for positron beam focusing at the ILC.

Findings

Simulations suggest the plasma lens design is feasible.

Preliminary results support further experimental and detailed modeling.

The approach could enhance positron capture efficiency.

Abstract

The International Linear Collider is a planned electron-positron linear collider with its positron source producing positrons by aiming undulator radiation onto a rotating target. The resulting, highly divergent positron beam requires immediate optical matching to improve the luminosity and therefore the success of the intended collision experiments. Here, optical matching refers to the process of capturing particles and making them available for downstream beamline elements like accelerators. In the past, this has been done with sophisticated coils, but more recently the usage of a current-carrying plasma, a so-called plasma lens, has been proposed as an alternative. For the International Linear Collider idealised particle tracking simulations have already been done with the purpose of finding the optimal plasma lens design with respect to the captured positron yield. The proposed design is characterised by a linearly widened radius in beam direction. Now further research and development of this design is required, including both experiments with a prototype set-up as well as corresponding simulations modelling the hydrodynamics of the current-carrying plasma and the resulting magnetic field. The accuracy of the latter will benefit greatly from the former. In this work, first preliminary hydrodynamic simulations instil confidence into further endeavours.