Enhanced betatron X-rays from axially modulated plasma wakefields

TL;DR

This paper demonstrates how axially modulated plasma wakefields induce unstable betatron oscillations, significantly enhancing the energy and brilliance of betatron X-ray emission in plasma accelerators.

Contribution

It introduces a novel method using axially modulated plasma to induce unstable betatron motion, improving X-ray output beyond previous limitations.

Findings

Unstable betatron oscillations increase X-ray energy.

Photon energy of X-rays is significantly enhanced.

Theoretical and simulation results confirm the effectiveness.

Abstract

In the cavitation regime of plasma-based accelerators, a population of high-energy electrons tailing the driver can undergo betatron motion. The motion results in X-ray emission, but the brilliance and photon energy are limited by the electrons' initial transverse coordinate. To overcome this, we exploit parametrically unstable betatron motion in a cavitated, axially modulated plasma. Theory and simulations are presented showing that the unstable oscillations increase both the total X-ray energy and average photon energy.