Probing the transient fields of the plasma accelerators with an ultrashort electron beam

FLASHForward, the exploratory FLASH beamline for Future-ORiented Wakefield Accelerator Research and Development, is a European pilot test bed facility for plasma-wakefield acceleration (PWFA) experiments. The goals of these experiments are to produce, in a few centimeters of ionized gas, beams of GeV energy with high quality, develop diagnostics for such beams, and evaluate their application in the fields of high energy physics and future compact light sources. Several conventional and novel diagnostics tools, capable of characterizing ultra-short plasma-wakefield accelerator beams, are under development in the FLASHForward diagnostic test laboratory. Notably, the Femtosecond innovative RelativistiC Electron (FiRCE) is a probe designed for investigation of plasma interaction region. Therefore, the FiRCE probe will aid in the understanding of the processes of electron trapping and acceleration in PWFA through the mapping of transient electric fields. In this contribution, a summary of the research and development related to the FiRCE probe, such as the parameter regime and set up requirements, is discussed.