Laser and Particle Beams

Research Article

Resonant acceleration of electrons by intense circularly polarized Gaussian laser pulses

H.Y. Niua1 c1, X.T. Hea2a3a4, B. Qiaoa2a5 and C.T. Zhoua2a3a4

a1 Graduate School of China Academy of Engineering Physics, Beijing, People's Republic of China

a2 Institute of Applied Physics and Computational Mathematics, Beijing, People's Republic of China

a3 Center for Applied Physics and Technology, Peking University, Beijing, People's Republic of China

a4 Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou, People's Republic of China

a5 Department of Physics, National University of Singapore, Singapore

Abstract

Resonant acceleration of plasma electrons in combined circularly polarized Gaussian laser fields and self-generated quasistatic fields has been investigated theoretically and numerically. The latter includes the radial quasistatic electric field, the azimuthal quasistatic magnetic field and the axial one. The resonant condition is theoretically given and numerically testified. The results show some of the resonant electrons are accelerated to velocities larger than the laser group velocity and thus gain high energy. For peak laser intensity I0 = 1 × 1020 W cm−2 and plasma density n0 = 0.1ncr, the relativistic electron beam with energies increased from 207 MeV to 262 MeV with a relative energy width around 24% and extreme low beam divergence less than 1° has been obtained. The effect of laser intensity and plasma density on the final energy gain of resonant electrons is also investigated.

(Received January 20 2008)

(Accepted February 03 2008)

Correspondence:

c1 Address correspondence and reprint requests to: H.Y. Niu, Graduate School of China Academy of Engineering Physics, PO Box 2101 Beijing 100088, People's Republic of China. E-mail: niuhaiyan221@126.com