Density gradients to reduce fluid instabilities in multishell inertial-confinement-fusion targets (original) (raw)

The Investigation of Rayleigh-Taylor Instability Growth Rate in Inertial Confinement Fusion

2009

In inertial confinement fusion, laser beams irradiate a small spherical capsule, causing it to implode. The compression of the capsule during the implosion creates conditions for nuclear fusion, a reaction where deuterium (D) and Tritium (T), two isotopes of hydrogen, collide and fuse, forming a larger Helium-4 atom as well as a neutron, thereby converting mass into kinetic energy. The laser pulse is designed to drive multiple shocks through the shell and to accelerate it to the implosion velocity required for ignition. The time interval corresponding to the shell acceleration is commonly referred to as the acceleration phase. The shocks set the shell on the desired adiabatic and merge into a single shock before reaching the shell's center. Such a single shock is reflected off the center and impulsively slows down the incoming shell. Additional shocks may be reflected off the shell and its center until the lower density material enclosed by the shell (the so-called hot spot) re...

Developing one-dimensional implosions for inertial confinement fusion science

High Power Laser Science and Engineering, 2016

Experiments on the National Ignition Facility show that multi-dimensional effects currently dominate the implosion performance. Low mode implosion symmetry and hydrodynamic instabilities seeded by capsule mounting features appear to be two key limiting factors for implosion performance. One reason these factors have a large impact on the performance of inertial confinement fusion implosions is the high convergence required to achieve high fusion gains. To tackle these problems, a predictable implosion platform is needed meaning experiments must trade-off high gain for performance. LANL has adopted three main approaches to develop a one-dimensional (1D) implosion platform where 1D means measured yield over the 1D clean calculation. A high adiabat, low convergence platform is being developed using beryllium capsules enabling larger case-to-capsule ratios to improve symmetry. The second approach is liquid fuel layers using wetted foam targets. With liquid fuel layers, the implosion con...

Implosion Physics, Alternative Targets Design and Neutron Effects on Inertial Fusion Systems

2000

A new radiation transport code has been coupled with an existing multimaterial fluidynamics code using Adaptive Mesh Refinement (AMR) and its testing is presented, solving ray effect and shadow problems in SN classical methods. Important advances in atomic physics, opacity calculations and NLTE calculations, participating in significant experiments (LULI/France), have been obtained. Our new 1D target simulation model allows considering