Multi-kT/m Focusing Gradient in a Linear Active Plasma Lens

TL;DR

This paper demonstrates that active plasma lenses with argon in a small capillary can produce highly linear magnetic focusing fields of 3.6 kT/m, significantly surpassing traditional quadrupole magnets, suitable for high-gradient beam focusing.

Contribution

The study shows that argon-filled plasma lenses can achieve a focusing gradient of 3.6 kT/m with linear magnetic fields, greatly exceeding previous results and quadrupole magnet capabilities.

Findings

Achieved 3.6 kT/m focusing gradient in plasma lens

Maintained linear magnetic fields at high gradients

Used compact Marx banks for repeatable current pulses

Abstract

Active plasma lenses are compact devices developed as a promising beam-focusing alternative for charged particle beams, capable of short focal lengths for high-energy beams. We have previously shown that linear magnetic fields with gradients of around 0.3 kT/m can be achieved in argon-filled plasma lenses that preserve beam emittance [C.A. Lindstr{\o}m et al., Phys. Rev. Lett. 121, 194801 (2018)]. Here we show that with argon in a 500 {\mu}m diameter capillary, the fields are still linear with a focusing gradient of 3.6 kT/m, which is an order of magnitude higher than the gradients of quadrupole magnets. The current pulses that generate the magnetic field are provided by compact Marx banks, and are highly repeatable. These results establish active plasma lenses as an ideal device for pulsed particle beam applications requiring very high focusing gradients that are uniform throughout the lens aperture.