Critical Layer Penetration in a Cold Z-Pinch Plasma by High-Intensity 10.6 Microns Laser Radiation.
MICHIGAN UNIV ANN ARBOR LASER PLASMA INTERACTION LAB
Pagination or Media Count:
The intensity dependence of transmission of high-intensity 10.6 microns laser radiation through an overdense cold Z-pinch plasma has been measured to determine a threshold for transmission. A holographic cinema of plasma evolution, obtained independently of the CO2 laser, provided initial information about the target plasma. An intensity threshold for transmission was measured to be about 2.5 x 10 to the 11 Wsq cm for incidence on the pre-pinch plasma, and 2 x 10 to the eleven Wsq cm for the post-pinch plasma. As the laser intensity was increased above threshold, compression of the transmitted pulse was observed from its incident width of 38 nsec to a transmitted width of 15 nsec at maximum intensity of 4 x 10 to the eleven Wcm. Coincidence measurements between the incident and transmitted pulse indicated the blockage of the first portion of the pulse and subsequent transmission of the remainder. Analysis of the laser-induced shock indicated about 60 to 70 percent energy absorption. Enhanced optical continuum emission from the interaction volume was attributed to plasma heating.
- Lasers and Masers
- Plasma Physics and Magnetohydrodynamics