Diffusive tunneling in an isobaric but non-isothermal fuel-pusher mixture*

Hydrodynamic mix of fusion fuel and inert pusher can simultaneouly generate smaller fuel pockets and finer pusher layers that separate them.  Smaller fuel pockets have greater local Knudsen numbers, which tend to excerberate the Knudsen layer reactivity reduction.  A thinner pusher layer separating the neighboring fuel pockets, on the other hand, can enable the diffusive tunneling of Gamow fuel ions through the pusher layer and hence alleviate the Knudsen layer reactivity degradation.  Here the diffusive tunneling phenomenon describes a
random walk process by which the Gamow fuel ions from one fuel pocket can traverse the inert pusher layer to join a neighboring fuel pocket without losing much of their energy.   In
an isobaric target mixture where fuel and pusher segments can have distinct temperatures, due to their different compressibilities, the temperature effect on the critical pusher layer areal density for diffusive tunneling, which is a property of the hydrodynamic mix, is understood by computing the ion charge state distribution using a collisional radiative model.  These information are fed into the collisionality evaluation, resulting a parametric scan of the diffusive tunneling physics in terms of the target pressure, fuel and pusher temperatures.