Incorporating kinetic effects on Nernst advection in inertial fusion simulations

We present a simple method to incorporate nonlocal effects on the Nernst advection of magnetic fields down steep temperature gradients, and demonstrate its effectiveness in a number of inertial fusion scenarios. This is based on assuming that the relationship between the Nernst velocity and the heat flow velocity is unaffected by nonlocality. The validity of this assumption is confirmed over a wide range of plasma conditions by comparing Vlasov-Fokker-Planck and flux-limited classical transport simulations. Additionally, we observe that the Righi-Leduc heat flow is more severely affected by nonlocality due to its dependence on high velocity moments of the electron distribution function, but are unable to suggest a reliable method of accounting for this in fluid simulations.