Spallation As The Dominant Source of Pusher-Fuel and Hot-Spot Mix In ICF Capsules
- Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
We report that the dominant source of pusher-fuel and hot-spot “mix” that has degraded the yields of modern ICF capsules designed and fielded to achieve high yield has likely been the spallation of small chunks or “grains” of pusher material into the fuel regions—not hydrodynamic instabilities. Such “spallation mix” occurs at the passage of the first strong shock whenever (1) the solid pusher adjacent to the fuel changes its phase by nucleation, and (2) such material when shocked (i.e., compressed and superheated, but still a solid) is subject to spallation when suddenly decompressed. When such spallation occurs, we show that it is the dominant mix mechanism by comparing the predictions of a spallation-mix model with measured experimental data, and by referring to direct experimental observations. We also explain how to eliminate this mix mechanism and thus allow higher yields for ICF capsules.
- Research Organization:
- Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC52-07NA27344
- OSTI ID:
- 1179113
- Report Number(s):
- LLNL-TR-665701
- Country of Publication:
- United States
- Language:
- English
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