title: Observation of a plasma waveguide in a preformed plasma pumped by double-pulse laser irradiation for the efficient soft x-ray amplification.
abstract: A molybdenum slab target was irradiated by double pulses of a line-focused chirped-pulse-amplification Nd:glass laser. A probe beam was injected in the plasma in the longitudinal direction, and we found that the probe beam was guided in the plasma with the plasma length of up to 4.3 mm at the time of 0.8-1.5 ns after the peak of the second pulse. Comparison with hydrodynamics code implied that the electron-density dip or flat region was formed, which was favorable for the efficient soft x-ray lasing under the coupling of the seed x-ray and the x-ray amplifier.
authors.affiliation: Quantum Beam Science Directorate, Japan Atomic Energency Agency, Umemidai, Kizugawa, Kyoto, Japan. kawachi.tetsuya@jaea.go.jp
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Kawachi
authors.forename: Noboru
authors.initials: N
authors.lastname: Hasegawa
authors.forename: Masaharu
authors.initials: M
authors.lastname: Nishikino
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Ochi
authors.forename: Akira
authors.initials: A
authors.lastname: Sasaki