Model Comparisons with STELLA Experimental Results

High-trapping efficiency and narrow energy spread in a staged laser acceleration system was demonstrated during the Staged Electron Laser Acceleration (STELLA) experiment. The experiment used inverse free electron lasers (IFEL) driven by the Brookhaven National Laboratory Accelerator Test Facility (ATF) CO2 laser. The First IFEL modulated the electron beam energy. A subsequent chicane created a train of ~3 fs-long microbunches separated by 10.6 mum. These microbunches are trapped and accelerated in a second IFEL, where up to 80% trapping efficiencies and energy spreads down to 0.36% (1) were measured. This paper presents additional model comparisons with the data, and discusses the strengths and limitations of the model.