Ablation of insulators under the action of short pulses of X-ray plasma lasers and free-electron lasers

プラズマX線レーザーと自由電子レーザーからの短パルスによる絶縁体の融除

Inogamov, N. A.*; Anisimov, S. I.*; Petrov, Y. V.*; Khokhlov, V. A.*; Zhakhovskii, V. V.*; Faenov, A. Ya.*; Pikuz, T.; Fortov, V. E.*; Skobelev, I. Y.*; 加藤 義章* ; Shepelev, V. V.*; 福田 祐仁; 田中 桃子; 石野 雅彦; 錦野 将元; 神門 正城; 河内 哲哉; 岸本 牧; 永園 充*; 登野 健介*; 石川 哲也*; 大橋 治彦*; 矢橋 牧名*; 富樫 格*; 仙波 泰徳*

Inogamov, N. A.*; Anisimov, S. I.*; Petrov, Y. V.*; Khokhlov, V. A.*; Zhakhovskii, V. V.*; Faenov, A. Ya.*; Pikuz, T.; Fortov, V. E.*; Skobelev, I. Y.*; Kato, Yoshiaki*; Shepelev, V. V.*; Fukuda, Yuji; Tanaka, Momoko; Ishino, Masahiko; Nishikino, Masaharu; Kando, Masaki; Kawachi, Tetsuya; Kishimoto, Maki; Nagasono, Mitsuru*; Tono, Kensuke*; Ishikawa, Tetsuya*; Ohashi, Haruhiko*; Yabashi, Makina*; Togashi, Tadashi*; Semba, Yasunori*

An experimental and theoretical study has been carried out of the ablation of a solid insulator with a wide band gap (LiF) under the action of ultrashort laser pulses of the UV range, obtained in a free-electron laser, and the soft X-ray region, obtained in a silver-plasma laser. A comparison is made of the results obtained on the two laser systems. It is shown that the ablation threshold is about the same for both lasers. A theory is presented that explains the weak growth of the ablation mass with increasing surface energy density of the laser radiation (the fluence) in the case of X-ray lasers as a result of the transition from spallation close to the ablation threshold to evaporative ablation at high fluence values.