ABSTRACT:
Typical descriptions of plasmas begin to break down as the density is increased or temperature is lowered. Collisions begin to dominate, the screening length becomes of order the inter-particle spacing, and potential energy can be as important as kinetic energy. I will quantify the importance of these effects and when they matter for stopping power. Stopping power describes the energy loss of a projectile moving through a medium. It provides a strong test of electron-ion collision operators for kinetic theory because it is a velocity-resolved transport property and so errors in stopping power models tells us information about how similar models will fail for other transport properties. I have used classical molecular dynamics simulations of stopping power to quantify the errors in these models over a broad range of conditions. I will also directly compare quantum calculations to new experimental results from the Omega laser facility.