How to Obtain a Bunch Length of 50 $\mu$ in the CLIC Main Linac

The revised list of parameters of the CLIC study according to the scaling laws includes a very short rms bunch length of 50 m in the main Linac for energies up to 1 TeV. This note presents a preliminary design of the bunch compressors based on RF pseudo rotators in the longitudinal phase plane requiring relatively low RF power and on standard magnetic chicanes. To achieve the high compression rate the first order analysis has been fully developed and optimised while magnetic high order effects and wakefields have been studied through a tracking program. Plots of the longitudinal phase plane simulation are shown which prove that the proposed Bunch Compressors are indeed able to provide a beam with such short bunch length while keeping high order effects at an acceptable level.