Giant Terahertz Pulses Generated by Relativistic Beam in a Dielectric Channel

TL;DR

This paper demonstrates that a relativistic electron beam in a dielectric channel can generate giant terahertz pulses with fields surpassing current methods, due to energy scaling with the Lorentz factor.

Contribution

It reveals how a beam offset in a dielectric channel produces large-scale electromagnetic fields with energy scaling as γ squared, enabling high-intensity terahertz pulse generation.

Findings

Electromagnetic field extends to large radii outside the channel.

Energy scales as the Lorentz factor squared, γ^2.

Resulting terahertz pulses can produce electric fields exceeding current standards.

Abstract

We analyze the electromagnetic field of a short relativistic electron beam propagating in a round, hollow dielectric channel. We show that if the beam propagates with an offset relative to the axis of the channel, in a steady state, its electromagnetic field outside of the channel extends to large radii and carries an energy that scales as the Lorentz factor $\gamma$ squared (in contrast to the scaling $\ln\gamma$ without the channel). When this energy is converted into a terahertz pulse and focused on a target, the electric field in the focus can greatly exceed typical values of the field that are currently achieved by sending beams through thin metallic foils.