Indirectly driven, high-convergence implosions (HEP1)
- and others
High-gain inertial confinement fusion will most readily be achieved with hot-spot ignition, in which a relatively small mass of gaseous fuel at the center of the target is heated to 5-10 keV, igniting a larger surrounding mass of approximately isobaric fuel at higher density but lower temperature. Existing lasers are too low in energy to achieve thermonuclear gain, but hydrodynamically equivalent implosions using these lasers can demonstrate that the important, scalable parameters of ignition capsules are scientifically and technologically achievable. The experiments described in this article used gas-filled glass shells driven by x rays produced in a surrounding cavity, or hohlraum. These implosions achieved convergence ratios (initial capsule radius/ final fuel radius) high enough to fall in the range required for ignition-scale capsules, and they produced an imploded configuration (high-density glass with hot gas fill) that is equivalent to the hot-spot configuration of an ignition-scale capsule. Other recent laser-driven implosions have achieved high shell density but at lower convergences and without a well defined hot spot. Still other experiments have used very-low-density gas fill to reach high convergence with unshaped drive, but that approach results in a relatively low shell density. Moreover, even at the highest convergence ratios the implosions described here had neutron yields averaging 8% of that calculated for an idealized, clean, spherically symmetric implosion - much higher than previous high-convergence experiments.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- OSTI ID:
- 376959
- Report Number(s):
- UCRL-LR-105820-95; ON: DE96013181; TRN: 96:004685-0025
- Resource Relation:
- Other Information: PBD: Jun 1996; Related Information: Is Part Of Inertial confinement fusion. 1995 ICF annual report, October 1994--September 1995; PB: 407 p.
- Country of Publication:
- United States
- Language:
- English
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