Ion acceleration via interaction of intense laser pulse with cluster-gas target

Fukuda, Yuji; Faenov, A.*; Tampo, Motonobu; Pikuz, T. A.*; Nakamura, Tatsufumi; Kando, Masaki; Hayashi, Yukio; Yogo, Akifumi; Sakaki, Hironao; Kawase, Keigo; Pirozhkov, A. S.; Ogura, Koichi; Mori, Michiaki; Esirkepov, T. Z.; Koga, J. K.; Yamauchi, Tomoya*; Kodama, Ryosuke*; Bolton, P.; Kondo, Kiminori; Kawanishi, Shunichi; Kato, Yoshiaki ; Tajima, Toshiki; Daido, Hiroyuki; Bulanov, S. V.

We present substantial enhancement of the accelerated ion energies up to 10-20 MeV per nucleon by utilizing the unique properties of the cluster-gas target irradiated with 40-fs laser pulses of only 150 mJ energy, corresponding to approximately tenfold increase in the ion energies compared to previous experiments using thin foil targets. A particle-in-cell simulation infers that the high energy ions are generated at the rear side of the target due to the formation of a strong dipole vortex structure in sub-critical density plasmas. The demonstrated method can be important in the development of efficient laser ion accelerators for hadron therapy and other applications.