Preliminary results from the CLEAR nonlinear plasma lens experiment

TL;DR

This paper reports preliminary experimental results on a nonlinear active plasma lens at CERN, aiming to achieve achromatic electron beam transport for plasma accelerators through controlled nonlinear focusing.

Contribution

It introduces a nonlinear active plasma lens with controlled focusing variation, a key component for achromatic transport in plasma accelerator stages.

Findings

Probing magnetic field structure of the lens using electron beams.

Observation of nonlinear focusing effects.

Supporting 2D plasma simulation results.

Abstract

Plasma lensing provides compact focusing of electron beams, since they offer strong focusing fields (kT/m) in both planes simultaneously. This becomes particularly important for highly diverging beams with a large energy spread such as those typically originating from plasma accelerators. The lens presented here is a nonlinear active plasma lens, with a controlled focusing-strength variation purposely introduced in one transverse direction. This lens is a key element of a larger transport lattice, core of the ERC project SPARTA, which aims to provide a solution for achromatic transport between plasma-accelerator stages. We report on preliminary experimental results from the CLEAR facility at CERN, which aims to probe the magnetic field structure of the lens using an electron beam, in search of the desired nonlinearity, together with 2D plasma simulation results.