Capsule Shimming Developments for National Ignition Facility (NIF) Hohlraum Asymmetry Experiments
- General Atomics, San Diego, CA (United States); General Atomics
- General Atomics, San Diego, CA (United States)
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Capsule drive in National Ignition Facility (NIF) indirect drive implosions is generated by x-ray illumination from cylindrical hohlraums. The cylindrical hohlraum geometry is axially symmetric but not spherically symmetric causing capsule-fuel drive asymmetries. We hypothesize that fabricating capsules asymmetric in wall thickness (shimmed) may compensate for drive asymmetries and improve implosion symmetry. Simulations suggest that for high compression implosions Legendre mode P4 hohlraum flux asymmetries are the most detrimental to implosion performance. General Atomics has developed a diamond turning method to form a GDP capsule outer surface to a Legendre mode P4 profile. The P4 shape requires full capsule surface coverage. Thus, in order to avoid tool-lathe interference flipping the capsule part way through the machining process is required. This flipping process risks misalignment of the capsule causing a vertical step feature on the capsule surface. Recent trials have proven this step feature height can be minimized to ~0.25 µm.
- Research Organization:
- General Atomics, San Diego, CA (United States)
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- NA0001808; AC52-07NA27344
- OSTI ID:
- 1402460
- Alternate ID(s):
- OSTI ID: 1458701
- Journal Information:
- Fusion Science and Technology, Journal Name: Fusion Science and Technology Journal Issue: 2 Vol. 73; ISSN 1536-1055
- Publisher:
- American Nuclear SocietyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Instability growth seeded by DT density perturbations in ICF capsules
|
journal | September 2018 |
Similar Records
First large capsule implosions in a frustum-shaped hohlraum
Low mode implosion symmetry sensitivity in low gas-fill NIF cylindrical hohlraums