students and some $5 million in funding are involved. These opportunities can be exploited most effectively by moving from the present National Laboratory-driven university grant program to the very successful user models in nuclear physics, high-energy physics, and basic energy sciences. Here, large facilities are regarded as tools available to both university and National Laboratory scientists for collaborative pursuit of shared scientific goals. Furthermore, university participants have typically been supported by funding independent of the National Laboratories, usually from either the DOE Office of Energy Research or the National Science Foundation.

CERTIFICATION OF WEAPONS STEWARDS

Predicting ICF results in well-diagnosed experiments and ultimately achieving ignition are in many respects more technically demanding than making a nuclear weapon work. Significant surprises in NIF results might be an objective signal of inadequacies in the SBSS program and would spur efforts to improve basic understanding of weapons physics.

Prior to the start of the moratorium on nuclear testing, weapons designers could unambiguously confirm judgment and refine their skills through the success or failure of their devices in underground tests. In the new era of a complete nuclear test ban, the NIF can provide weapons stewards with a similarly challenging alternative for refining and proving their skills. Hydrodynamic motion, radiation flow in diverse geometries, and ultimately capsule ignition and burn would be examined in great detail in NIF experiments. The ability to do "pre-shot" modeling of these phenomena will be a significant certification of weapons stewards' skills and a continuing challenge for those skills.

CODE VALIDATION AND MATERIALS PROPERTIES

Several relatively new experimental programs exploit lasers and pulsed power to collect data and validate the weapons physics in codes relevant to SBSS. These efforts are aimed at understanding genuinely three-dimensional systems and measuring opacities, equations of state, the dynamic response of materials, hydrodynamics, and radiative transfer. These studies do not have sharp requirements in laser energy or performance; indeed, they have been carried out at NOVA, as well as at the LANL Trident laser facility, NRL's NIKE laser facility, and LLE's OMEGA. However, the NIEF would carry these studies into new and more relevant domains.

It is expected that the NIF would provide a controlled environment from which extensive and novel data can be extracted for both ICF and SBSS applications. Such data are critical for the validation of the design codes that are applied to ICF targets and are relevant to the prediction, evaluation, and analysis of weapons physics issues. While other facilities are expected to provide similar data, the NIF would access different regimes of such parameters as temperature, density, and scale length. This full suite of data is required to attempt to meet SBSS objectives under the Comprehensive Test Ban Treaty.

The complex physics involved in ICF and SBSS studies implies a corresponding complexity in the radiation-hydrodynamics codes used; these codes push the state of the art in many ways, including differencing methods, parallel computation techniques, and physics modules. Even in the absence of ignition, the NIF has key roles to play in the maturation, maintenance, and advanced development of these codes, which have a use in other DOE technical and scientific programs.

In addition to providing data for critical, yet standardized, tests of codes (including grid resolution and convergence studies), the NIF environment would allow some of the physics models involved to be developed, tested, and evaluated. Since a first-principles formulation of such models is generally not possible at this time, the phenomenology used must be calibrated against an extensive and reliable database spanning the range of expected conditions. The NIF may be the best tool to provide this calibration for many of the models of interest.

For example, ions with high atomic number have a complex set of electronic configurations and ionization states whose descriptions strain both computational and experimental techniques. A benchmark class of experiments with the NIF will both calibrate and validate advanced computer codes that can be used to extend opacity tables and equation-of-state formulae into regimes important to both



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