Coherent Radiation in Insertion Devices

TL;DR

This paper calculates the coherent radiation emitted in insertion devices like undulators and wigglers with arbitrary vacuum chamber shapes, highlighting the wavelength and directional properties of the radiation.

Contribution

It provides a general method to compute coherent radiation in insertion devices with arbitrary chamber geometries, extending previous models.

Findings

Backward radiation is coherent with wavelengths about twice the undulator period.

Most coherent radiation occurs at wavelengths approximately equal to the bunch length.

Coherent radiation is emitted at small angles relative to the device axis.

Abstract

We calculate the coherent radiation in an undulator/wiggler with a vacuum chamber of arbitrary cross section. The backward radiation is a coherent and it has wavelengths about twice the period of the undulator/wiggler. Mostly of coherent radiation is going with the wavelengths approximately the bunch length at small angles however.