Hydrodynamic growth and mix experiments at National Ignition Facility

[摘要] Hydrodynamic growth and its effects on implosion performance and mix were studied at the National Ignition Facility (NIF). Spherical shells with pre-imposed 2D modulations were used to measure Rayleigh-Taylor (RT) instability growth in the acceleration phase of implosions using in-flight x-ray radiography. In addition, implosion performance and mix have been studied at peak compression using plastic shells filled with tritium gas and imbedding localized CD diagnostic layer in various locations in the ablator. Neutron yield and ion temperature of the DT fusion reactions were used as a measure of shell-gas mix, while neutron yield of the TT fusion reaction was used as a measure of implosion performance. The results have indicated that the low-mode hydrodynamic instabilities due to surface roughness were the primary culprits to yield degradation, with atomic ablator-gas mix playing a secondary role.

[发布机构] Lawrence Livermore National Laboratory, NIF Dir., Livermore; CA; 94550, United States^1;Los Alamos Na National Laboratory, Los Alamos; NM; 97544, United States^2;General Atomics, San Diego; CA; 92186, United States^3;Laboratory for Laser Energetics, University of Rochester, Rochester; NY; 14623, United States^4

[关键词] Acceleration phase;Hydrodynamic instabilities;Ion temperature;National ignition facility;Peak compression;Rayleigh-Taylor instabilities;Spherical shell;Yield degradation