Single Shot Characterization of High Transformer Ratio Wakefields in Nonlinear Plasma Acceleration

Experimental Demonstration of Double Emittance Exchange toward Arbitrary Longitudinal Beam Phase-Space Manipulations

Many of the most significant advances in accelerator science have been due to improvements in our ability to manipulate beam phase space. Despite steady progress in beam phase-space manipulation over the last several decades, future accelerator applications continue to outpace the ability to manipulate the phase space. This situation is especially pronounced for longitudinal beam phase-space manipulation, and is now getting increased attention. Herein, we report the first experimental demonstration of the double emittance exchange concept, which allows for the control of the longitudinal phase space using relatively simple transverse manipulation techniques. The double emittance exchange beamline enables extensive longitudinal manipulation, including tunable bunch compression, time-energy correlation control, and nonlinearity correction, in a remarkably flexible manner. The demonstration of this new method opens the door for arbitrary longitudinal beam manipulations capable of responding to the ever increasing demands of future accelerator applications.

High-resolution sampling of beam-driven plasma wakefields

Plasma-wakefield accelerators driven by intense particle beams promise to significantly reduce the size of future high-energy facilities. Such applications require particle beams with a well-controlled energy spectrum, which necessitates detailed tailoring of the plasma wakefield. Precise measurements of the effective wakefield structure are therefore essential for optimising the acceleration process. Here we propose and demonstrate such a measurement technique that enables femtosecond-level (15 fs) sampling of longitudinal electric fields of order gigavolts-per-meter (0.8 GV m^-1). This method-based on energy collimation of the incoming bunch-made it possible to investigate the effect of beam and plasma parameters on the beam-loaded longitudinally integrated plasma wakefield, showing good agreement with particle-in-cell simulations. These results open the door to high-quality operation of future plasma accelerators through precise control of the acceleration process.