Novel studies of plasma ion stopping power in moderately-coupled and degenerate plasmas using knock-on deuteron spectra*

Charged particle spectroscopy is routinely used to diagnose properties of Inertial Confinement Fusion (ICF) implosions such as the areal density (ρR). ρR is determined from the measured mean energy of emitted charged particles compared to their known birth energy. Such measurement depends on accurately knowing the plasma stopping-power – the rate at which charged particles lose energy while traversing the implosion's dense shell. However, multiple competing plasma stopping-power formalisms exist, and none have been thoroughly validated for moderately coupled and degenerate plasmas. A new study is presented that contrasts measured stopping power of knock-on deuterons from one-dimensional DT gas-filled CD-capsule implosions, to simulated values for plasmas with coupling parameters and degeneracy values of 0.1–0.5 and 1–10, respectively. The simulations use the Monte-Carlo particle tracing code IRIS, which has multiple plasma stopping-power formalisms built in. These results provide the first accurate validation of various stopping power formalisms for a range of ion velocities in moderately-coupled and degenerate plasmas.