Optimization of laser parameters to obtain high-energy, high-quality electron beams through laser-plasma acceleration

• Published in: Physics of plasmas 2010-10, Vol.17 (10), p.103110-103110-11
• Main Authors: Samant, Sushil Arun, Sarkar, Deepangkar, Upadhyay, Ajay K., Krishnagopal, Srinivas, Jha, Pallavi
• Format: Article
• Language: English
• Subjects: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ACCELERATION; ACCELERATORS; BEAM-PLASMA SYSTEMS; BEAMS; ELECTRON BEAMS; FREE ELECTRON LASERS; HOMOGENEOUS PLASMA; LASERS; LEPTON BEAMS; LINEAR ACCELERATORS; OPTIMIZATION; PARTICLE ACCELERATORS; PARTICLE BEAMS; PLASMA; PLASMA ACCELERATION; PLASMA DENSITY; PLASMA SIMULATION; SIMULATION; TWO-DIMENSIONAL CALCULATIONS; WAKEFIELD ACCELERATORS
• ISSN: 1070-664X; 1089-7674
• DOI: 10.1063/1.3496382

The propagation of an intense ( a 0 = 3 ) , short-pulse ( L ∼ λ p ) laser through a homogeneous plasma has been investigated. Using two-dimensional simulations for a 0 = 3 , the pulse-length and spot-size at three different plasma densities were optimized in order to get a better quality beam in laser wakefield accelerator. The study reveals that with increasing pulse-length the acceleration increases, but after a certain pulse-length ( L > 0.23 λ p ) the emittance blows-up unacceptably. For spot-sizes less than that given by k p 0 r s = 2 a 0 , trapping is poor or nonexistent, and the optimal spot-size is larger. The deviation of the optimal spot-size from this formula increases as the density decreases. The efficacy of these two-dimensional simulations has been validated by running three-dimensional simulations at the highest density. It has been shown that good quality GeV-class beams can be obtained at plasma densities of ∼ 10 18   cm − 3 . The quality of the beam can be substantially improved by selecting only the high-energy peak; in this fashion an energy-spread of better than 1% and a current in tens of kA can be achieved, which are important for applications such as free-electron lasers.