Modeling of a cold velvet cathode electron beam with discrete electronic emission

An inductive voltage adder named “Mi2” has been built at Commissariat à l’Énergie Atomique et aux Energies Alternatives to produce two intense pulsed electron beams of 2 kA, 700 keV, and 80 ns full width at half maximum from a cold velvet cathode. In a coupling of experimental and simulation studies, we aim to evaluate the emittance value of those beams. This study focuses on the first beam modelization. Multidimensional particle-in-cell simulation models are used to demonstrate the necessity of taking into account the discrete nature of the electronic emission in order to model a beam consistent with the experimental studies. This study also shows the influence of the emissive surface geometry on the beam current density and emittance and provides a numerical model matching the first beam structure.