Direct-drive-ignition designs with mid-Z ablators

作者：Lafon M^*; Betti R; Anderson K S; Collins T J B; Epstein R; McKenty P W; Myatt J F; Shvydky A; Skupsky S

来源：Physics of Plasmas, 2015, 22(3): 032703.

DOI：10.1063/1.4914835

Achieving thermonuclear ignition using direct laser illumination relies on the capability to accelerate spherical shells to high implosion velocities while maintaining shell integrity. Ablator materials of moderate atomic number Z reduce the detrimental effects of laser-plasma instabilities in direct-drive implosions. To validate the physics of moderate-Z ablator materials for ignition target designs on the National Ignition Facility (NIF), hydro-equivalent targets are designed using pure plastic (CH), high-density carbon, and glass (SiO2) ablators. The hydrodynamic stability of these targets is investigated through two-dimensional (2D) single-mode and multimode simulations. The overall stability of these targets to laser-imprint perturbations and low-mode asymmetries makes it possible to design high-gain targets. Designs using polar-drive illumination are developed within the NIF laser system specifications. Mid-Z ablator targets are an attractive candidate for direct-drive ignition since they present better overall performance than plastic ablator targets through reduced laser-plasma instabilities and a similar hydrodynamic stability.

• 出版日期2015-3