An Adiabatic Phase-Matching Accelerator

TL;DR

This paper introduces a novel adiabatic phase-matching accelerator using a tapered dielectric-lined waveguide, capable of efficiently accelerating non-relativistic electrons over short distances, with potential applications in advanced accelerators and electron diffraction.

Contribution

It proposes a new adiabatic tapering scheme for dielectric waveguides supporting phase-matched acceleration of non-relativistic particles, validated by simulations and beam dynamics analysis.

Findings

Accelerates 200 keV electrons to 10 MeV over 10 cm

Achieves peak electric fields of 100 MV/m

Demonstrates potential for compact advanced accelerators

Abstract

We present a general concept to accelerate non-relativistic charged particles. Our concept employs an adiabatically-tapered dielectric-lined waveguide which supports accelerating phase velocities for synchronous acceleration. We propose an ansatz for the transient field equations, show it satisfies Maxwell's equations under an adiabatic approximation and find excellent agreement with a finite-difference time-domain computer simulation. The fields were implemented into the particle-tracking program {\sc astra} and we present beam dynamics results for an accelerating field with a 1-mm-wavelength and peak electric field of 100~MV/m. The numerical simulations indicate that a $\sim 200$-keV electron beam can be accelerated to an energy of $\sim10$~MeV over $\sim 10$~cm. The novel scheme is also found to form electron beams with parameters of interest to a wide range of applications including, e.g., future advanced accelerators, and ultra-fast electron diffraction.