# Landau Damping of Beam Instabilities by Electron Lenses

## TL;DR

This paper demonstrates that electron lenses can effectively provide Landau damping to suppress transverse beam instabilities in high-intensity accelerators, outperforming traditional nonlinear elements like octupoles.

## Contribution

It introduces the use of electron lenses as a novel, efficient method for Landau damping in particle accelerators, especially for future high-energy colliders.

## Key findings

- Electron lenses can stabilize beams more effectively than thousands of octupoles.
- Electron lenses focus frequency spread at the beam core, minimizing lifetime degradation.
- A single electron lens can outperform extensive octupole magnet arrays.

## Abstract

Modern and future particle accelerators employ increasingly higher intensity and brighter beams of charged particles and become operationally limited by coherent beam instabilities. Usual methods to control the instabilities, such as octupole magnets, beam feedback dampers and use of chromatic effects, become less effective and insufficient. We show that, in contrast, Lorentz forces of a low-energy, a magnetically stabilized electron beam, or "electron lens", easily introduces transverse nonlinear focusing sufficient for Landau damping of transverse beam instabilities in accelerators. It is also important that, unlike other nonlinear elements, the electron lens provides the frequency spread mainly at the beam core, thus allowing much higher frequency spread without lifetime degradation. For the parameters of the Future Circular Collider, a single conventional electron lens a few meters long would provide stabilization superior to tens of thousands of superconducting octupole magnets.

---
Source: https://tomesphere.com/paper/1706.08477