Laser plasma accelerator: Control of electron beam parameters in colliding laser pulses scheme

Stable and high quality electron beams are produced when two laser pulses collide in underdense plasmas. In addition to the improvement of the stability of the electron beam, the use of a second laser pulse allows the control of the electron beam parameters (energy, relative energy spread, and charge). The experimental features are well explained by the use of PIC simulations which underline physics processes which were not predicted by fluid model. This control is obtained by changing laser pulse energy, laser pulses polarization or electron density. With a total of 1 J laser energy, a 10 pC electron beam at 200 MeV with relative energy spread smaller than 1\% has been measured for the first time. Using higher laser energy PIC simulations predicted that 3 GeV electron beam with 0.9\% should be produced in this scheme after 3.8 cm propagation length. In collaboration with J. Faure and C. Rechatin, Laboratoire d'Optique Appliqu\'ee, \'Ecole Nationale Sup\'erieure de Techniques Avanc\'ees, \'Ecole Polytechnique, CNRS, UMR 7639, 91761 Palaiseau, France; A. Ben-Ismail, Laboratoire d'Optique Appliqu\'ee, and LLR, \'Ecole polytechnique, CNRS-IN2P3, 91128 Palaiseau, France; J. Lim, Laboratoire d'Optique Appliqu\'ee; X. Davoine and E. Lefebvre, Commissariat \`a l'Energie Atomique, DIF, Bruy\`eres-le-Ch\^atel, France; and A. Specka and H. Videau, LLR, \'Ecole polytechnique. \\[2pt] This work has been partially supported by ANR-05-NT05-2-41699, by the European Community Research Infrastructure Activity under the FP6 Structuring the European Research Area program (CARE, contract number RII3-CT-2003-506395 and EU-ROLEAP, contract number 028514).