title: Laser-hole boring into overdense plasmas measured with soft X-Ray laser probing
abstract: A laser self-focused channel formation into overdense plasmas was observed using a soft x-ray laser probe system with a grid image refractometry (GIR) technique. 1.053 &mgr;m laser light with a 100 ps pulse duration was focused onto a preformed plasma at an intensity of 2x10(17) W/cm (2). Cross sections of the channel were obtained which show a 30 &mgr;m diameter in overdense plasmas. The channel width in the overdense region was kept narrow as a result of self-focusing. Conically diverging density ridges were also observed along the channel, indicating a Mach cone created by a shock wave due to the supersonic propagation of the channel front.
authors.affiliation: Institute of Laser Engineering, Osaka University, Yamada Oka 2-6, Suita, Osaka 565-0871, Japan.
authors.initials: K
authors.lastname: Takahashi
authors.initials: R
authors.lastname: Kodama
authors.initials: KA
authors.lastname: Tanaka
authors.initials: H
authors.lastname: Hashimoto
authors.initials: Y
authors.lastname: Kato
authors.initials: K
authors.lastname: Mima
authors.initials: FA
authors.lastname: Weber
authors.initials: TW
authors.lastname: Barbee
authors.lastname: Da Silva LB