High resolution X-ray spectroscopy of plasma irradiated by ultra-short laser pulses with intensities of 10 W/cm

Faenov, A.*; Hansen, S. B.*; Colgan, J.*; Abdallah, J.*; Pikuz, T.; Pikuz, S. A.*; Skobelev, I. Y.*; Nishiuchi, Mamiko; Sakaki, Hironao; Maeda, Shota; Sagisaka, Akito; Pirozhkov, A. S.; Ogura, Koichi; Fukuda, Yuji; Kanasaki, Masato; Matsukawa, Kenya*; Hasegawa, Noboru; Nishikino, Masaharu; Kando, Masaki; Yamauchi, Tomoya*; Watanabe, Yukinobu*; Zhidkov, A.*; Kawachi, Tetsuya; Kondo, Kiminori

We present new set of measurements of high spectrally resolved K-shell spectra of Al and Fe plasma obtained by thin foils irradiation using 40 fs laser pulses of J-KAREN laser facility with intensities up to 10 W/cm. Dependences of X-ray spectra from laser energy and thicknesses of foils were investigated. Measured power-law dependence of X-ray intensity vs laser beam intensity confirmed that at laser intensities higher than 10 W/cm Radiation Dominated regime could be reached. Two independent models are used to provide a detail theoretical study of the various configurations and processes roles in the formation of the observed spectra. Modeling demonstrated strong influence of X-ray photo pumping from laser-produced plasma for intensity and structure of observed X-ray spectra.