Simulation of monoenergetic electron generation via laser wakefield accelerators for 5–25 TW lasers

In 2004, using a 3D particle-in-cell PIC model F. S. Tsung et al., Phys. Rev. Lett. 93, 185004 2004 , it was predicted that a 16.5 TW, 50 fs laser propagating through nearly 0.5 cm of 3 1018 cm−3 preformed plasma channel would generate a monoenergetic bunch of electrons with a central energy of 240 MeV after 0.5 cm of propagation. In addition, electrons out to 840 MeV were seen if the laser propagated through 0.8 cm of the same plasma. The simulations showed that self-injection occurs after the laser intensity increases due to a combination of photon deceleration, group velocity dispersion, and self-focusing. The monoenergetic beam is produced because the injection process is clamped by beam loading and the rotation in phase space that results as the beam dephases. Nearly simultaneously S. P. D. Mangles et al., Nature 431, 535 2004 ; C. G. R. Geddes et al., ibid. 431, 538 2004 ; J. Faure et al., ibid. 431, 541 2004 three experimental groups from around the world reported the generation of near nano-Coulomb of low emittance, monoenergetic electron beams using similar laser powers and pulse lengths as those reported in our simulations. Each of these experiments is modeled using the same 3D PIC code OSIRIS. The simulations indicate that although these experiments use a range of plasma parameters, density profiles, laser powers, and spot sizes; there are some commonalities to the mechanism for the generation of monoenergetic beams. Comments are given on how the energy and beam quality can be improved in the future. © 2006 American Institute of Physics. DOI: 10.1063/1.2198535