Abstract Details
Simulations of shock-ignited inertial-confinement-fusion targets with
Author: Jason W. Bates
Requested Type: Oral Only
Submitted: 2009-04-21 19:49:27
Co-authors: A.J. Schmitt, S.P. Obenschain, D.E. Fyfe, S.T. Zalesak
Contact Info:
U.S. Naval Research Laboratory
4555 Overlook Avenue, SW
Washington, DC 20375
USA
Abstract Text:
In this talk, we report on recent numerical simulations of inertial-confinement-fusion implosions using the FAST radiation hydro-code at the U.S. Naval Research Laboratory. Our discussion focuses on a particular class of "shock-ignited" [1] target designs utilizing approximately 1 MJ of direct KrF laser light that is "zoomed" to maximize coupling efficiency. In the shock ignition approach, a moderate-intensity, compressive laser pulse is followed by a short-duration high-intensity "spike," which launches a spherically-convergent shock wave into the target to ignite the core of compressed fuel. Such an arrangement appears to offer several significant advantages, including a theoretically-lower ignition threshold, higher gain, and greater resistance to the deleterious effects of laser-plasma instabilities. According to one-dimensional simulations, fusion gains over 200 can be achieved with shock-ignited targets using only 700-800 kJ of laser energy. This represents a significant improvement in performance over conventional centrally-ignited designs. Moreover, the lower in-flight aspect ratio of shock-ignited targets implies an enhanced robustness with regard to hydrodynamic instability growth during the acceleration phase of the implosion ---- an expectation that we closely examine through the presentation of numerous two-dimensional simulations. Of particular interest in our analysis of these results are the optimum pulse parameters for this class of target designs, as well as the constraints placed on surface fabrication tolerances and laser illumination uniformity.
[1] R. Betti, C.D. Zhou, K.S. Anderson, et al., Phys. Rev. Lett. 98, 155001 (2007).
Comments: