Capsule implosion optimization during the indirect-drive National Ignition Campaign

Abstract

Capsule performance optimization campaigns will be conducted at the National Ignition Facility [G. H. Miller, E. I. Moses, and C. R. Wuest, Nucl. Fusion 44, 228 (2004)] to substantially increase the probability of ignition. The campaigns will experimentally correct for residual uncertainties in the implosion and hohlraum physics used in our radiation-hydrodynamic computational models using a variety of ignition capsule surrogates before proceeding to cryogenic-layered implosions and ignition experiments. The quantitative goals and technique options and down selections for the tuning campaigns are first explained. The computationally derived sensitivities to key laser and target parameters are compared to simple analytic models to gain further insight into the physics of the tuning techniques. The results of the validation of the tuning techniques at the OMEGA facility [J. M. Soures et al., Phys. Plasmas 3, 2108 (1996)] under scaled hohlraum and capsule conditions relevant to the ignition design are shown to meet the required sensitivity and accuracy. A roll-up of all expected random and systematic uncertainties in setting the key ignition laser and target parameters due to residual measurement, calibration, cross-coupling, surrogacy, and scale-up errors has been derived that meets the required budget. Finally, we show how the tuning precision will be improved after a number of shots and iterations to meet an acceptable level of residual uncertainty.

Energy and wavelength scaling of shock-ignited inertial fusion targets

“…A comment is probably in place concerning reliability of studies based on analytical models and one-dimensional (1D) numerical simulations, in light of the recent results [18,19] of the National Ignition Campaign (NIC) [20]. NIC experiments so far have shown implosion velocity smaller than predicted (at a given laser power) [18].…”

Assembly of High-Areal-Density Deuterium-Tritium Fuel from Indirectly Driven Cryogenic Implosions

“…A strategy to achieve high-R implosions using indirectly driven capsules on the National Ignition Facility (NIF) [4] is described in a series of articles by Landen, Haan, Edwards et al, [5][6][7]. This methodology requires experiments to optimize implosion symmetry [8], laserhohlraum coupling [9], and accurate timing of the shocks that drive the implosion [10,11].…”

Technical Applications of the Physics of High Energy Densities

“…7.26 [117] and 7.27. The fine tuning of laser radiation parameters and fusion target characteristics in an effort to achieve ignition is the concern of [156]. 24 Thermonuclear plasma parameters measured from X-ray and neutron radiations [97] The experiments made to date have yielded the highest Lawson-criterion values for all controlled fusion facilities: P 10 atm s (see Chap.…”