Figure 3 Target ignition regimes plotted vs. peak power in terawatts and peak energy in megajoules. The laser plasma and hydrodynamic instability regions are indicated. An ignition target design is indicated along with the National Ignition Facility baseline and maximum safe operating power-energy curves. Source: Lawrence Livermore National Laboratory.

NIF. The NIF laser design provides an estimated factor-of-two safety margin above the estimated ignition threshold.1

Beamlet Performance as Validation of the NIF Design

The NIF laser will operate with larger optics than any previous laser system. Figure 4 shows schematics of the NIF and the Beamlet laser designs. The two designs are substantially similar, with minor differences in the size of the optical components, the injection into the 4-pass laser amplifier, and turning mirrors between the NIF laser and the harmonic converter. Figure 5 shows the comparison of the Beamlet performance and the expected NIF beamline performance at 1050 nm. The Beamlet operates over the peak power/pulse-energy region projected for the NIF,2 with recent experience demonstrating the expected performance. The Beamlet has operated at the intensity/output-fluence levels projected for a NIF beamline, for pulses from 1 ns to 10 ns, and has exceeded the nominal NIF operating point.3

1  

S.W. Haan et al. "Ignition Target Design for the National Ignition Facility," Inertial Confinement Fusion, UCRL-LR-105821-95-4, Vol. 5, No. 4, p. 215–225, 1995.

2  

 LLNL ICF Program, presentation to NIF Laser Subcommittee, Inertial Confinement Fusion Advisory Committee/Defense Programs (ICFAC/DP), L-17459, Vol. 2, April 20–23, 1994.

3  

 LLNL ICF Program, presentation to National Research Council's Committee for the Review of the Department of Energy's Inertial Confinement Fusion Program (U), L-22838-01, August 1–2, 1996.



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