Probing ion species separation and ion thermal decoupling in shock-driven implosions using multiple nuclear reaction histories

Simultaneously measured DD, DT, and (DHe)-He-3 reaction histories are used to probe the impacts of multi-ion physics during the shock phase of inertial confinement fusion implosions. In these relatively hydrodynamiclike (burn-averaged Knudsen number NK similar to 0.3) shock-driven implosions, average-ion hydrodynamic DUED simulations are able to reasonably match burnwidths, nuclear yields, and ion temperatures. However, kinetic-ion FPION simulations are able to better simulate the timing differences and time-resolved reaction rate ratios between DD, DT, and (DHe)-He-3 reactions. FPION simulations suggest that the (DHe)-He-3/DT reaction rate ratio is most directly impacted by ion species separation between the He-3 and T ions, whereas the (DHe)-He-3/DD reaction rate ratio is affected by both ion species separation and ion temperature decoupling effects