Amplification of a surface electromagnetic wave by running over plasma surface ultrarelativistic electron bunch as a new scheme for generation of Teraherz radiation

TL;DR

This paper presents a theoretical scheme for amplifying surface electromagnetic waves using ultrarelativistic electron bunches over plasma surfaces, potentially enabling high-power Terahertz radiation generation without magnetic fields.

Contribution

It introduces a novel theoretical model for wave amplification by ultrarelativistic electron bunches, showing conditions for high saturation fields and energy densities surpassing bunch energy.

Findings

Saturation field of surface EM wave can reach significant levels without wave breakdown.

Surface wave energy density can exceed the electron bunch energy density.

Potential for generating superpower Terahertz radiation is discussed.

Abstract

The amplification of a surface electromagnetic wave by means of ultrarelativistic monoenergetic electron bunch running over the flat plasma surface in absence of a magnetic field is studied theoretically. It is shown that when the ratio of electron bunch number density to plasma electron number density multiplied by a powered to 5 relativity factor is much higher than 1, i.e $\gamma^5 n_b/n_p>> 1$, the saturation field of the surface electromagnetic wave induced by trapping of bunch electrons gains the magnitude: $E_x=B_y\approx 0.16 \frac{\omega_p m c}{e} (\frac{2n_b}{\gamma^2 n_p})^{1/7}$ and does not approache the surface electromagnetic wave front breakdown threshold in plasma. The surface electromagnetic wave saturation energy density in plasma can exceed the electron bunch energy density. Here, we discuss the possibility of generation of superpower Teraherz radiation on a basis of such scheme.