Production of Cumulative Jets Generated by Laser-Driven Collapsing Hollow Cones and Wedges*

Cumulative plasma jets formed by imploding hollow cones and wedges are observed. The cones, made from 4-10 mg/cm$^{2 }$Ni or Al foils, with a base diameter of 500 $\mu $m and 90 - 130$^{o}$ apex angles, are imploded by a 1.054-$\mu $m wavelength, $\sim $4 ns FWHM laser pulse focused to $\sim $ 2*10$^{13}$ W/cm$^{2}$ on their outer surface. Jet shape, location, and densities are measured with monochromatic radiography utilizing 0.65 keV x-rays. For certain cone geometries, cumulative jets with ion densities $>$10$^{19}$ cm$^{-3}$ propagate at velocities $>$10 km/sec. The interaction of such jets with an ambient medium and the resulting shock structures can be used for lab simulation of aspects of various astrophysical phenomena such as jets produced in supernovae explosions or accretion of plasma onto compact objects (black hole, neutron star or white dwarf).