The Nike Direct-Drive ICF Program

摘要

The Nike program coordinates experimental and theoretical efforts to evaluate and verify the physics base needed to proceed with direct-drive inertial confinement fusion. The program emphasizes the use of KrF laser drivers because of their demonstrated ultra-smooth target illumination and high absorption efficiency but is also applicable to short-wavelength glass laser drivers. Currently, the Nike program is concentrating on the problem of increasing the gain of direct-drive target designs while simultaneously minimizing the growth of hydrodynamic instabilities. Advanced target designs have been identified which achieve low isentropic compression while reducing RT instability through the use of tuned soft x-ray or shock preheating of the target ablator. Experiments measure the growth and saturation of the ablative RT instability and its modification as a result of tuning of the ablator isentrope and variations in laser imprinting. The important fundamental processes are also investigated in individual experiments to measure the emission and transport of x-ray radiation, the equations-of-state of deuterium, foams, and other relevant materials, as well as the acceleration of cryogenic filled foams.