Radial focusing and energy compression of a laser-produced proton beam by a synchronous rf field oleh Masahiro Ikegami, Shu Nakamura, Yoshihisa Iwashita, Toshiyuki Shirai, Hikaru Souda, Yujiro Tajima, Mikio Tanabe, Hiromu Tongu, Hiroyuki Itoh, Hiroki Shintaku, Atsushi Yamazaki, Hiroyuki Daido, Akifumi Yogo, Satoshi Orimo, Michiaki Mori, Mamiko Nishiuchi, Koichi Ogura, Akito Sagisaka, Alexander S. Pirozhkov, Hiromitsu Kiriyama, Shyuhei Kanazawa, Shuji Kondo, Yoichi Yamamoto, Takuya Shimomura, Manabu Tanoue, Yoshimoto Nakai, Atsushi Akutsu, Sergei V. Bulanov, Toyoaki Kimura, Yuji Oishi, Koshichi Nemoto, Toshiki Tajima, Akira Noda