Prof Peter Norreys FInstP;

Abstract:

A novel technique of time-resolved monochromatic X-ray imaging has been used to measure the spatial variation of burn through time of an ablator layer on spherical targets irradiated by twelve laser beams of wavelength 0.53 μm and pulse duration 0.8 ns at adsorbed irradiance up to 1014 W cm-2. The effect of beam overlap on uniformity has been studied. © 1988.

Abstract:

An instrumental technique for recording monochromatic X-ray images of laser-produced plasmas has been developed using a Layered Synthetic Microstructure in combination with a pinhole camera. Well resolved images in 6 Å X-ray emission from 10 μm gold microdots are demonstrated. © 1987.

Abstract:

Inertial confinement fusion fuel suffers increased X-ray radiation losses when carbon from the capsule ablator mixes into the hot-spot. Here we present one and two-dimensional ion VlasovFokker-Planck simulations that resolve hot-spot self heating in the presence a localised spike of carbon mix, totalling 1.9 % of the hot-spot mass. The mix region cools and contracts over tens of picoseconds, increasing its alpha particle stopping power and radiative losses. This makes a localised mix region more severe than an equal amount of uniformly distributed mix. There is also a purely kinetic effect that reduces fusion reactivity by several percent, since faster ions in the tail of the distribution are absorbed by the mix region. Radiative cooling and contraction of the spike induces fluid motion, causing neutron spectrum broadening. This artificially increases the inferred experimental ion temperatures and gives line of sight variations.