Emittance self-compensation in blow-out mode

Abstract

We report an unusual regime of emittance self-compensation in an electron bunch generated in blow-out mode by a radio-frequency photocathode gun. Simulations clearly show an initial growth and a subsequent self-compensation of projected emittance in a divergent electron bunch originating from the effects of: (i) strong space-charge forces of mirror charges on the cathode, (ii) an energy chirp in the bunch and (iii) substantial re-shaping of the electron bunch. Furthermore, we show analytically and numerically how a complex interplay between these effects leads to emittance self-compensation in free space -- the effect that is normally observed only in a focusing magnetic field.

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• Nano-modulated electron beams via electron diffraction and emittance exchange for coherent x-ray generation
• Comment on "How to Realize Uniform Three-Dimensional Ellipsoidal Electron Bunches"