51. X-ray spectroscopy evidence of solid-density ultra-relativistic laser plasma in renewable micron-scale cryogenic clusters targets
- Author
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N. Ryazantsev, S., A. Pikuz, T., A. Pikuz, S., Kaji, T., Tanabe, H., Nakagawa, T., Takafumi, Asai, Kanasaki, M., Oda, K., Yamauchi, T., Jinno, S., Taguchi, T., K. Himeno, Iwasaki, K., Hihara, T., Sakai, K., Minami, T., Abe, Y., Tokiyasu, A., Kohri, H., Kuramitsu, Y., Sakawa, Y., Yasuhiro, Miyasaka, Kotaro, Kondo, Akira, Kon, Akito, Sagisaka, Koichi, Ogura, Pirozhkov, Alexander, Masaki, Kando, Kiminori, Kondo, Tetsuya, Kawachi, Hiromitsu, Kiriyama, Yuji, Fukuda, and Yuuji, Fukuda
- Abstract
Recently it was shown that injection of gas preliminary cooled down to cryogenic temperatures is a promising way to produce micron-scale clusters. For example, in hydrogen clusters with the size up to ≈2 μm were produced via a conical nozzle at 25 K, 6 MPa. Micron scale clusters can be also created with another pre-cooled gases, for example Ar or Kr, but for other temperature values. So large clusters diameter value becomes comparable with a waist width of a laser beam produced by the J-KAREN-P laser facility. As a result, an experimental case can occur, when most of the laser energy is absorbed in a single cluster. Such situation can be considered as an interaction of a laser pulse with matter, state of which is close to solid-state. In the presentation plasma X-ray spectra features indicating the described case of high-intensity laser and large-scale-cluster interaction are discussed. They were observed experimentally during irradiation of cryogenic (T = 140 K – 220 K) Ar flows by ultra-intensive (I = 10^22 W/cm^2) femtosecond laser pulses generated by the J-KAREN-P laser. Registered X-ray spectra of produced plasma contains Ar XVIII Ly-α and Ar XVII He-α of comparable intensities. It should be noted that the Ar XVIII Ly-α line has been for the first time observed in laser-matter interaction experiments. It indicates that the density of irradiated matter is high enough to provide a rate of impact ionization process, which is sufficient to create a significant amount of H-like Ar ions. It is a challenge to reach such condition for a pure gas or small clusters. Thus, the observed spectra are considered as an evidence of a large micron cluster existing in the beam waist region., International Conference on High Energy Density Sciences (HEDS2021)
- Published
- 2021