Core contributions to stopping powers in warm dense matter

Core electron excitations constitute a significant energy loss mechanism for ions traversing matter with velocities beyond the Bragg peak. However, little is known about the relative importance of contributions from different core shells, particularly at high temperatures, where modified binding energies and occupations alter the energetics and Pauli blocking of available transitions. Here, we use real-time time-dependent density functional theory (TDDFT) and a recently developed, cost-reducing scheme for optimizing projectile trajectories to compute temperature-dependent, velocity-dependent, and orbital-resolved contributions to proton stopping powers in warm dense lithium, sodium, and aluminum. We also evaluate techniques to calculate these core contributions from computationally efficient average atom methods. This work advances the understanding of fundamental mechanisms underlying stopping power in extreme conditions and the accuracy of materials models used in the design and interpretation of fusion experiments.