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

Abstract

Simultaneously measured DD, DT, and D3He 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⟩ ∼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 D3He reactions. FPION simulations suggest that the D3He/DT reaction rate ratio is most directly impacted by ion species separation between the 3He and T ions, whereas the D3He/DD reaction rate ratio is affected by both ion species separation and ion temperature decoupling effects.