CERN Accelerating science

Article
Title	Terahertz IFEL/FEL Microbunching for Plasma Beatwave Accelerators
Author(s)	Sung, Chieh ; Clayton, Chris ; Joshi, Chandrashekhar ; Musumeci, Pietro ; Pellegrini, Claudio ; Ralph, Joseph ; Reiche, Sven ; Rosenzweig, James E ; Tochitsky, Sergei Ya
Affiliation	(UCLA, Los Angeles, California)
Publication	2005
In:	21st IEEE Particle Accelerator Conference, Knoxville, TN, USA, 16 - 20 May 2005, pp.2812
Subject category	Accelerators and Storage Rings
Abstract	In order to obtain monoenergetic acceleration of electrons, phase-locked injection using electron microbunches shorter than the accelerating structure is necessary. For a laser-driven plasma beatwave accelerator experiment, we propose to microbunch the electrons by interaction with terahertz (THz) radiation in an undulator via two mechanisms– free electron laser (FEL) and inverse free electron laser (IFEL). Since the high power FIR radiation will be generated via difference frequency mixing in GaAs by the same CO2 beatwave used to drive the plasma wave, electrons could be phase-locked and pre-bunched into a series of microbunches separated with the same periodicity. Here we examine the criteria for undulator design and present simulation results for both IFEL and FEL approaches. Using different CO2 laser lines, electrons can be microbunched with different periodicity 300 – 100 mm suitable for injection into plasma densities in the range 1016 – 1017 cm-3, respectively. The requirement on the THz radiation power and the electron beam qualities are also discussed.