Evolution of surface structure in laser-preheated perturbed materials

Abstract

We report an experimental and computational study investigating the effects of laser preheat on the hydrodynamic behavior of a material layer. In particular, we find that perturbation of the surface of the layer results in a complex interaction, in which the bulk of the layer develops density, pressure, and temperature structure, and in which the surface experiences instability-like behavior, including mode coupling. A uniform one-temperature preheat model is used to reproduce the experimentallyobserved behavior, and we find that this model can be used to capture the evolution of the layer, while also providing evidence of complexities in the preheat behavior. This result has important consequences for inertially-confined fusion plasmas, which can be difficult to diagnose in detail, as well as for laser hydrodynamics experiments, which generally depend on assumptions about initial conditions in order to interpret their results.

High-flux high-energy ion beam production from stable collisionless shock acceleration by intense petawatt-picosecond laser pulses

“…The target combining the near critical plasmas and the high density tube is complicated. However, as the rapid and significant technological advances have been made in the target fabrication [57], the target described in this paper can now or very soon be manufactured, where the tube can be filled with foams [38], cryogenic hydrogen microjet [39] or high-pressure gas jets [40]. In order to make the proposed scheme work properly without prematurely expansion of the tube wall, a laser contrast of 10 10 is required, which is available by using the plasma mirrors [58,59].…”

Demonstration of repeatability in a high-energy-density planar shear mixing layer experiment

“…[12] We only change the tracer layer characteristics to vary the initial conditions that seed the KH evolution. Each different set of tracer layer characteristics, such as tracer layer material [12,13] or surface profile [15,16], is considered it own campaign.…”

Measurement of Preheat Due to Nonlocal Electron Transport in Warm Dense Matter

“…Alternative fusion schemes such as fast ignition rely on heating of fusion targets by energy deposition of electrons [6,7]. Preheat of target components due to X-rays and energetic particles in laser-driven HED systems is a well-known problem causing changes in initial conditions and multiple hydrodynamic instabilities in EOS and ICF experiments [9,10]. Specifically electron transport in dense laser-heated plasmas holds the key to understanding many fundamental questions [11].…”