Electron and photon acceleration by interaction between laser and plasma

Kotaki, Hideyuki; Hayashi, Yukio; Mori, Michiaki; Kando, Masaki; Koga, J. K.; Bulanov, S. V.

In laser-plasma interaction, there are physical phenomena, such as quantum beam generation, relativistic self-focusing of laser pulses, frequency up-shift of laser pulses, etc. The generated electron beam has an ultrashort pulse width of the order of femtoseconds or less. In applications of these electron beams, stable and controllable electron beams are necessary. Stable and monoenergetic electron beams have been generated in the self-injection scheme of laser acceleration. The electron beam has 4 fs (FWHM). For the stable electron beam generation, long plasma channel formation via self-focusing is an important mechanism. We measured forward scattered radiation and an accelerated electron beam. In the spectrum, we observed a big frequency up-shift due to the change of the relativistic index and photon acceleration. The frequency up-shift changes the critical power of the self-focusing. The plasma channel is limited by the change of the power.