Simulation of the Gas Filling and Evacuation Processes in an Inertial Confinement Fusion (ICF) Hohlraum

In indirect inertial confinement fusion (ICF), the prediction of gas pressures and mass flow rates in the hohlraum is critical for fielding the hohlraum film and the support tent. To this end, it is desirable to understand the gas filling and evacuation process through the microcapillary fill tube and the support tent. In this work, a unified flow simulation of the filling and evacuation processes through the microcapillary fill tube and the support tent in an ICF hohlraum was conducted to study the gas pressure and mass flow rate in the hohlraum. The effects of the support tent size and the microcapillary fill tube size on the critical pressure variation and pressure difference across the hole on the support tent are examined. The results indicate that an increase in the diameter of the hole and the hole number leads to a smaller pressure difference across the hole on the support tent. If the diameter of the hole on the support tent is larger than 0.06 mm, the critical pressure variation rate is nearly independent of the diameter and the hole number. Increases in the diameter and decreases in the length of the microcapillary fill tube induce a larger critical pressure variation rate and pressure difference across the hole, which is conductive to fielding the hohlraum film.

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Theoretical Investigation of Gas Filling and Leaking in Inertial Confinement Fusion Hohlraum

Sustainability ◽

10.3390/su10103763 ◽

2018 ◽

Vol 10 (10) ◽

pp. 3763 ◽

Cited By ~ 1

Author(s):

Cheng Yu ◽

Suchen Wu ◽

Weibo Yang

Keyword(s):

Pressure Difference ◽

Inertial Confinement Fusion ◽

Polymeric Films ◽

Lower Probability ◽

Maximum Pressure ◽

Inertial Confinement ◽

Cross Sectional ◽

Confinement Fusion ◽

Variation Rate ◽

Sectional Shape

The gas filling and retention of inertial confinement fusion (ICF) hohlraum is an important issue in ICF studies. In this study, a theoretical model of gas filling and leaking processes for ICF hohlraum is developed based on the unified flow theory. The effects of the fill tube size and the filling pressure on the gas filling and leaking performance are investigated. The results indicate that an increase in the variation rate of the filling/leaking pressure leads to a larger maximum pressure difference between the inside and outside of the ICF hohlraum during the filling/leaking process. The critical pressure difference of the filling process is nearly equal to that of the leaking process. Increase in fill tube diameter and decrease in its length both lead to a lower probability of the rupture of polymeric films at two ends of the hohlraum, and thus increases the security of the hohlraum. In addition, a departure in cross sectional shape of fill tube from circle to rectangle triggers an increase in pressure difference between the inside and outside of the ICF hohlraum, which raises the risk of polymeric films rupture and decreases the security of the hohlraum structure.

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Analysis of electroless nickel thin films

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100086854 ◽

1991 ◽

Vol 49 ◽

pp. 510-511 ◽

Cited By ~ 1

Author(s):

C. W. Price ◽

E. F. Lindsey

Keyword(s):

Thin Films ◽

Inertial Confinement Fusion ◽

Electroless Nickel ◽

Inertial Confinement ◽

Plating Bath ◽

X Ray ◽

Nickel Thin Films ◽

Nickel Deposits ◽

Confinement Fusion ◽

Thickness Measurements

Thickness measurements of thin films are performed by both energy-dispersive x-ray spectroscopy (EDS) and x-ray fluorescence (XRF). XRF can measure thicker films than EDS, and XRF measurements also have somewhat greater precision than EDS measurements. However, small components with curved or irregular shapes that are used for various applications in the the Inertial Confinement Fusion program at LLNL present geometrical problems that are not conducive to XRF analyses but may have only a minimal effect on EDS analyses. This work describes the development of an EDS technique to measure the thickness of electroless nickel deposits on gold substrates. Although elaborate correction techniques have been developed for thin-film measurements by x-ray analysis, the thickness of electroless nickel films can be dependent on the plating bath used. Therefore, standard calibration curves were established by correlating EDS data with thickness measurements that were obtained by contact profilometry.

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