Smalyuk, V.A. and Betti, R. and Delettrez, J.A. and Glebov, V.Y. and Meyerhofer, D.D. and Radha, P.B. and Regan, S.P. and Sangster, T.C. and Sanz, Javier and Seka, W. and Stoeckl, C. and Yaakobi, B. and Frenje, J.A. and Li, C.K. and Petrasso, R.D. and Séguin, F.H.
Implosion Experiments using Glass Ablators for Direct-Drive Inertial Confinement Fusion..
"Physical Review Letters", v. 104
Direct-drive implosions with 20-μm-thick glass shells were conducted on the Omega Laser Facility to test the performance of high-Z glass ablators for direct-drive, inertial confinement fusion. The x-ray signal caused by hot electrons generated by two-plasmon-decay instability was reduced by more than ∼40× and hot-electron temperature by ∼2× in the glass compared to plastic ablators at ignition-relevant drive intensities of ∼1×1015 W/cm2, suggesting reduced target preheat. The measured absorption and compression were close to 1D predictions. The measured soft x-ray production in the spectral range of ∼2 to 4 keV was ∼2× to 3× lower than 1D predictions, indicating that the shell preheat caused by soft x-rays is less than predicted. A direct-drive-ignition design based on glass ablators is introduced.