Controlling nonlinear longitudinal space charge oscillations for high peak current bunch train generation

Abstract

The evolution of picosecond modulations of the longitudinal profile of an electron beam generated in an rf photoinjector is analyzed and optimized with the goal of obtaining high peak current electron bunch trains at very high frequencies (! THz). Taking advantage of nonlinear longitudinal space charge forces, it is found that more than 500 A peak current 1 THz bunch trains can be generated using a standard 1.6 cell SLAC/UCLA/BNL rf gun. Postacceleration is used to freeze the longitudinal phase space dynamics after one half plasma oscillation. Applications range from tunable narrow bandwidth THz radiation generation to drivers for high frequency high gradient accelerators.

Beam manipulation and acceleration with Dielectric-Lined Waveguides

“…These results are comparable to the ones experimentally obtained through wave-breaking in Ref. [81] albeit with a much higher contrast ratio [91]. The origin of the non-uniform bunching across the beam with peak-to-peak variation in the microbunch current is twofold.…”

Ballistic bunching of photoinjected electron bunches with dielectric-lined waveguides

“…These results are comparable to the ones experimentally obtained through wave breaking in Ref. [22] albeit with a much higher contrast ratio [42]. The origin of the nonuniform bunching across the beam with peak-topeak variation in the microbunch current is twofold.…”

Correlated Energy-Spread Removal with Space Charge for High-Harmonic Generation

“…LSC effects in high-brightness beams have been examined recently in various different contexts, including the microbunching instability (see e.g., [11,12]), LSC amplifiers [13,14], shot noise suppression schemes [15][16][17][18], and as a method to generate a train of high peak-current bunches [19,20]. Physically, LSC effects arise from the self-fields generated by longitudinal density perturbations in the beam.…”