Demonstration of mix mitigation and record performance using continuous dopant targets in ICF implosions on the NIF

In inertial confinement fusion experiments performed on the NIF, hard x-ray preheat of the DT fuel is controlled and mitigated via the addition of tungsten doping to the capsule's high-density carbon (HDC) ablator wall. Typically, this is implemented as a thin layer of uniform dopant concentration. While effective in controlling preheat and easy to manufacture, this uniform doping scheme introduces discontinuities in x-ray opacity and resulting shell density during the implosion, which are unstable to hydrodynamic mixing. To address this, we tested a novel, continuous doping strategy, where the tungsten concentration smoothly ramps up from zero at the inner shell surface to a maximum value, and then ramps back down to zero. As discussed in the previous presentation, modeling suggests this approach reduces hydrodynamic instabilities and mixing, thereby improving compression and yield. This presentation will discuss first experimental results from testing this new dopant profile, which resulted in a factor of two yield increase compared to its box-profile dopant comparison experiment, and a maximum yield of 8.6 MJ.