Extreme radiation emission regime for electron beams in strong focusing ion channels and undulators

TL;DR

This paper develops a new theoretical framework to accurately compare radiation emission in undulators and ion channels at high parameters, correcting previous underestimations and aligning predictions with numerical simulations.

Contribution

It introduces a redefinition of plasma density and undulator strength to improve predictions of particle behavior in high $k$ and $K/\gamma$ regimes, enabling better comparison of radiation sources.

Findings

Redefinition of plasma density and undulator strength improves accuracy.

Theoretical predictions match numerical simulations across regimes.

Differences in spectral features are clarified through simulations.

Abstract

A fundamental comparison between undulator and ion channel radiation is presented. Conventional theory for both devices fails to describe high $k$ and $K/\gamma$ regimes accurately, providing an underestimation of particle trajectory amplitude and period. This may lead to incorrect estimation of radiation emission in many setups of practical interest, such as the ion column. A redefinition of plasma density and undulator strength expressions leads to a more reliable prediction of particle behaviour, reproducing the closest possible conditions in the two devices and correctly matching expected betatron oscillation amplitude and wavelength for a wide range of $K/\gamma$ values. Differences in spectral features of the two devices can then be addressed via numerical simulations of single particle and beam dynamics. In this paper we outline a theoretical framework and compare its results with numerical simulation applied to setups eligible for possible radiation sources.