A new method of optical guidance by the implosion phase of a fast Z-pinch discharge in a gas-filled capillary is proposed. An imploding plasma column has a concave electron-density profile in the radial direction, just before a stagnation phase driven by a converging current sheet and a shock wave. The feasibility of optical guidance of a high-intensity (>1 × 1017 W/cm2) Ti:sapphire laser pulse by use of this method over a distance of 2 cm, corresponding to 12.5 times the Rayleigh length, has been experimentally demonstrated. The guiding-channel formation process was directly probed with a He–Ne laser beam. The electron density in the fully ionized channel was estimated to be 2.0 × 1017 cm-3 on the axis and 7.0 × 1017 cm-3 on the peaks of the channel edge, with a diameter of 70 μm, as indicated by the experimental results, which were corroborated by a magnetohydrodynamics simulation.
© 2000 Optical Society of America
[Optical Society of America ]
Tomonao Hosokai, Masaki Kando, Hideki Dewa, Hideyuki Kotaki, Syuji Kondo, Noboru Hasegawa, Kazuhisa Nakajima, and Kazuhiko Horioka, "Optical guidance of terrawatt laser pulses by the implosion phase of a fast Z-pinch discharge in a gas-filled capillary," Opt. Lett. 25, 10-12 (2000)