STUDIES OF THE COMPRESSION DYNAMICS OF INTERMEDIATE-DENSITY Z-PINCHES

The evolution of a constriction in a dense Z-pinch is studied in the M odule A5-I installation (0.04 Omega output resistance, 1.3 MA load cur rent, and 100 ns current rise time). Agar-agar fibers (2-3 mm in diame ter) with a preformed constriction (0.1-0.5 mm in diameter) are used a s a load. The fiber mass density is varied within a wide range from 10 (-2) to 10(-1) g/cm(3). The conditions under which the constriction st arts to develop are studied, and the parameters of the produced hot de nse plasma are measured using various X-ray diagnostics. The configura tion of the current channel is determined by simultaneously employing the laser shadow photography, the interferometric measurements with th e visualization of images, and the measurement of the Faraday rotation of the plane of polarization of the probing laser beam. It is shown t hat, as a result of the onset of the neck instability, a hot, dense pl asma with a temperature of 0.8-1.5 keV, electron density of 10(22) cm( 3), and characteristic size less than 80 mu m is produced in the const riction.