FUSION NEUTRONS FROM THE GAS-PUSHER INTERFACE IN DEUTERATED-SHELL INERTIAL CONFINEMENT FUSION IMPLOSIONS

The first measurements and numerical simulations of fusion neutrons fr om the gas-pusher interface of indirectly-driven inertial confinement fusion implosions have been performed using hydrogen-filled capsules m ade with a deuterated inner layer. Nonlinear saturation of the growth of hydrodynamic perturbations in high linear growth factor (similar or equal to 325) implosions was varied by adjusting the initial surface roughness of the capsule. The neutron yields are in quantitative agree ment with the direct simulations of perturbation growth, and also with a linear mode superposition and saturation model including enhanced t hermal loss in the mixed region. Neutron spectra from these capsules a re broader than expected for the calculated ion temperatures, suggesti ng the presence of nonthermal broadening from mass motion during the f usion burn. (C) 1998 American Institute of Physics.