Excitation of wakefields in carbon nanotubes: a hydrodynamic model approach

TL;DR

This paper models the excitation of electromagnetic wakefields in carbon nanotubes using a hydrodynamic approach, providing insights into optimizing conditions for potential high-gradient particle acceleration.

Contribution

It introduces a hydrodynamic model for analyzing wakefield excitation in carbon nanotubes, including derivation of general expressions and numerical analysis of parameter effects.

Findings

Wakefield amplitude depends on particle velocity and position

Optimal parameters can maximize longitudinal wakefield

Friction factor models ionic lattice effects

Abstract

The interactions of charged particles with carbon nanotubes may excite electromagnetic modes in the electron gas produced in the cylindrical graphene shell constituting the nanotube wall. This wake effect has recently been proposed as a potential novel method of short-wavelength high-gradient particle acceleration. In this work, the excitation of these wakefields is studied by means of the linearized hydrodynamic model. In this model, the electronic excitations on the nanotube surface are described treating the electron gas as a 2D plasma with additional contributions to the fluid momentum equation from specific solid-state properties of the gas. General expressions are derived for the excited longitudinal and transverse wakefields. Numerical results are obtained for a charged particle moving within a carbon nanotube, paraxially to its axis, showing how the wakefield is affected by parameters such as the particle velocity and its radial position, the nanotube radius, and a friction factor, which can be used as a phenomenological parameter to describe effects from the ionic lattice. Assuming a particle driver propagating on axis at a given velocity, optimal parameters were obtained to maximize the longitudinal wakefield amplitude.