Smith-Purcell radiation on a surface wave

TL;DR

This paper investigates Smith-Purcell radiation generated by electrons moving over a surface wave, analyzing conditions for enhanced and partially coherent radiation from electron bunches with asymmetric density profiles.

Contribution

It provides a theoretical analysis of radiation from electrons over arbitrary surface wave profiles, including conditions for coherence in electron bunches.

Findings

Radiation exceeds incoherent levels under specific conditions.

Partially coherent radiation occurs for short wavelengths relative to bunch length.

Asymmetric electron density distributions influence coherence properties.

Abstract

We consider the radiation from an electron in flight over a surface wave of an arbitrary profile excited in a plane interface. For an electron bunch the conditions are specified under which the overall radiation essentially exceeds the incoherent part. It is shown that the radiation from the bunch with asymmetric density distribution of electrons in the longitudinal direction is partially coherent for waves with wavelengths much shorter than the characteristic longitudinal size of the bunch.