Using HT and DT gamma rays to diagnose mix in Omega capsule implosions

9th International Conference on Inertial Fusion Sciences and Applications

Schmitt, M.J.^1 ; Herrmann, H.W.^1 ; Kim, Y.H.^1 ; McEvoy, A.M.^1 ; Zylstra, A.^1 ; Hammel, B.A.^2 ; Sepke, S.M.^2 ; Leatherland, A.^1 ; Gales, S.^3

Los Alamos National Laboratory, Los Alamos

MS

87545, United States^1

Lawrence Livermore National Laboratory, 7000 East Ave, Livermore

CA

94550, United States^2

Atomic Weapons Establishment, Aldermaston, Reading, Berkshire

RG7 4PR, United Kingdom^3

关键词: Experimental evidence;    Hydrodynamic mixing;    Interface mixing;    Interface temperatures;    Plastic capsule;    Shell materials;    Shell thickness;    Temporal measurements;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/717/1/012048/pdf
DOI  :  10.1088/1742-6596/717/1/012048

来源: IOP

【 摘 要 】

Experimental evidence [1] indicates that shell material can be driven into the core of Omega capsule implosions on the same time scale as the initial convergent shock. It has been hypothesized that shock-generated temperatures at the fuel/shell interface in thin exploding pusher capsules diffusively drives shell material into the gas core between the time of shock passage and bang time. We propose a method to temporally resolve and observe the evolution of shell material into the capsule core as a function of fuel/shell interface temperature (which can be varied by varying the capsule shell thickness). Our proposed method uses a CD plastic capsule filled with 50/50 HT gas and diagnosed using gas Cherenkov detection (GCD) to temporally resolve both the HT "clean" and DT "mix" gamma ray burn histories. Simulations using Hydra [2] for an Omega CD-lined capsule with a sub-micron layer of the inside surface of the shell pre-mixed into a fraction of the gas region produce gamma reaction history profiles that are sensitive to the depth to which this material is mixed. An experiment to observe these differences as a function of capsule shell thickness is proposed to determine if interface mixing is consistent with thermal diffusion λii∼T2/Z2ρ at the gas/shell interface. Since hydrodynamic mixing from shell perturbations, such as the mounting stalk and glue, could complicate these types of capsule-averaged temporal measurements, simulations including their effects also have been performed showing minimal perturbation of the hot spot geometry.