Correlated electron beam microbunching and shot-noise characterization with near-and far-field optical transition radiation

In this work we demonstrate how to analyze the dynamics of the correlated longitudinal current noise above andbelow the Poissonian shot-noise level in an e-beam, by calculating the emitted transition radiation (OTR) using acomplex vector field formulation which is exact in the near and far fields. We simulate a non-zero emittanceelectron beam, uncorrelated in the transverse cross section, but with different types of longitudinal correlations,resulting in coherent optical transition radiation. We show how this method is applied on the opposite case(suppression), by tracking simulated beam particles that correlate due to quarter-plasma oscillation during drift,and show how the OTR tracks the dynamics of the electron beam noise level.