Experimental studies of the high and low frequency electromagnetic radiation produced from nonlinear laser-plasma interactions

Kando, Masaki; Pirozhkov, A. S.; Fukuda, Yuji; Esirkepov, T. Z.; Daito, Izuru; Kawase, Keigo; Ma, J. L.*; Chen, L. M.*; Hayashi, Yukio; Mori, Michiaki; Ogura, Koichi; Kotaki, Hideyuki; Sagisaka, Akito; Ragozin, E. N.*; Faenov, A. Y.; Pikuz, T.*; Kiriyama, Hiromitsu; Okada, Hajime; Kameshima, Takashi; Koga, J. K.; Belyaev, K.*; Kamenets, F. F.*; Sugiyama, Akira; Kawachi, Tetsuya; Daido, Hiroyuki; Kimura, Toyoaki*; Kato, Yoshiaki* ; Tajima, Toshiki; Bulanov, S. V.

Nonlinear interaction of intense laser beams with plasma causes a number of different regimes of generation of high energy particle beams and of strong radiation with the emitted photon energy from the X-ray to THz frequency range. The review of the first proof-of-principle experiment and the latest progress on the flying mirror is presented. A low frequency EM radiation emission has also been observed in our experiments. The interpretation invokes the relativistic electromagnetic solitons. The solitons are formed in an underdense plasma in the process of the laser pulse frequency downshift. They store a portion of EM wave energy with the polarization inherited from the laser and emit it at the plasma-vacuum interface in a form of the low frequency EM bursts. We present the results of the polarization-resolved measurements.