Optical frequency shot-noise suppression in electron beams: Three-dimensional analysis

Abstract

A predicted effect of current shot-noise suppression at optical-frequencies in a drifting charged-particle-beam and the corresponding process of particles self-ordering are analyzed in a one-dimensional ͑1D͒ model and verified by three-dimensional numerical simulations. The analysis confirms the prediction of a 1D single mode Langmuir plasma wave model of longitudinal plasma oscillation in the beam, and it defines the regime of beam parameters in which this effect takes place. The suppression of relativistic beam shot noise can be utilized to enhance the coherence of free electron lasers and of any coherent radiation device using an electron beam.

Much Ado about Microbunching: Coherent Bunching in High Brightness Electron Beams

“…Past work on noise suppression resulting from plasma oscillations has found that 3D models lead to weaker noise suppression [14,15]. In our 1D model we assume a rigid sheet of charge that moves uniformly due to the average longitudinal field, whereas in reality each particle moves independently.…”

“…2.6). This may correspond to analogous differences between 3D and 1D models in suppression through plasma oscillations [14,15].…”

“…Shot noise also competes with external modulations in the operation of seeded FELs [12,13]. Recent papers have proposed schemes to suppress the noise level below that of shot noise to aid the FEL process [14,15,16]. In Chapter 2…”

“…Shot noise also competes with external modulations in the operation of seeded FELs [12,13]. Recent papers have proposed schemes to decrease the noise level below that of shot noise to aid the FEL process or for other applications [14,15,16]. In this chapter we use the approach of [17] to study the evolution of noise as the beam travels through a system with interactions between the electrons as well as dispersive regions.…”

“…Particles that are closer (farther) than the inter-particle spacing, ∆z < 1/n 0 , lose (gain) energy relative to the previous particle, and move away ( 2. 15 Comparison of 1D and 3D models for both r = 0 (red curves) and transverse average (blue).…”