V. W. Slivinsky

Interaction of 1.06 μm laser radiation with variable Z̃ targets

Parylene (C8H8) and tungsten‐glass (W2O/P2O5) disks have been irradiated with 150–400 psec Nd:YAG‐glass laser pulses focused to diameters of 250–300 μm with flux levels in the 1013–1015 W/cm2 range. An extensive array of diagnostics was used to measure the temporal and energy distributions of the focused laser light at the target, the angular distribution of the scattered laser light, the x‐ray spatial and spectral emission characteristics, and the emitted ion and electron distributions. Analysis of the experimental results indicates that the laser‐plasma interaction was characterized by a variety of collective phenomena which appeared stronger in the tungsten‐glass experiments.

Pinhole imaging of laser-produced thermonuclear alpha particles

We have built a pinhole camera for imaging the deuterium‐tritium (DT) burn region of laser‐driven implosions by spatially resolving the α particles. Kodak Pathe LR‐115 cellulose nitrate film was used as a detector with an 8‐mg/cm2 Ta filter. Initial results show that the α particles are produced in a region which is much smaller than the initial glass microsphere.

Diagnostics of Shiva Nova high-yield thermonuclear events

Experiments with the Shiva Nova laser facility which produce yield levels of scientific break-even and above will result in neutron, x ray, and particle fluxes which will require specific attention to the survivability of diagnostic instrumentation. These yield levels will also allow the utilization of new diagnostics techniques which can provide detailed information on the state of the imploded fuel and pusher shells.

Implosion experiments with an asymmetrically irradiated laser fusion target

A spherical glass microsphere filled with DT gas and mounted on a glass plate was imploded with a single neodymium glass laser beam. Volume compression ratios of 50-100 fold and 104 14 MeV neutrons were observed.

Use of argon x‐ray lines for the diagnosis of laser‐produced implosions

We have measured the spatial extent of heliumlike and hydrogenlike argon x‐ray lines that were emitted from the fuel region of an imploded laser fusion target directly illuminated by the Argus laser. The diameter of the fuel region measured in this way agrees with that obtained from images of the thermonuclear burn region recorded simultaneously by an alpha‐particle zone plate camera. Time‐averaged electron temperatures in the target core were determined from argon line intensity ratios and compared to ion temperatures determined from measurements of neutron yield.