Electron acceleration in a helical waveguide

TL;DR

This paper investigates electron acceleration in a helical waveguide, presenting methods to determine wave modes and addressing challenges with deformations affecting the solution's convergence.

Contribution

It introduces a partial wave expansion and point matching method for mode determination, and proposes two approaches to handle strong deformations in the waveguide.

Findings

PWE provides rapid solutions for moderate deformations.

Strong deformations increase acceleration but cause divergence in PWE.

Two new methods improve analysis for highly deformed guides.

Abstract

Travelling wave in a helical wave guide is considered for electron acceleration. A first determination of the travelling wave modes using a partial wave expansion (PWE) and a point matching method is presented. It gives a rapid solution for moderate deformation of the guide relative to a straight cylinder. Strong deformations will give higher accelerating gradient but the PWE diverges. Two methods overcoming this difficulties are suggested.