Direct-drive DT implosions with Knudsen number variations

[摘要] Direct-drive implosions of DT-filled plastic-shells have been conducted at the Omega laser facility, measuring nuclear yields while varying Knudsen numbers (i.e., the ratio of mean free path of fusing ions to the length of fuel region) by adjusting both shell thickness (e.g., 7.5, 15, 20, 30 μm) and fill pressure (e.g., 2, 5, 15 atm). The fusion reactivity reduction model showed a stronger effect on yield as the Knudsen number increases (or the shell thickness decreases). The Reduced-Ion-Kinetic (RIK) simulation which includes both fusion reactivity reduction and mix model was necessary to provide a better match between the observed neutron yields and those simulated.

[发布机构] Los Alamos National Laboratory, Los Alamos; NM; 87545, United States^1;Atomic Weapons Establishment, Aldermaston, Reading, Berkshire; RG7 4PR, United Kingdom^2;Massachusetts Institute of Technology, Cambridge; MA; 02139, United States^3;Laboratory for Laser Energetics, Rochester; NY; 14623, United States^4

[关键词] Direct drive implosion;Filled plastics;Knudsen numbers;Mean free path;Neutron yields;OMEGA Laser Facility;Reduction models;Shell thickness