High-Fidelity Particle-in-Cell Simulations of Thermionic Converters

Plasma-based thermionic energy converters (TECs) feature non-equilibrium processes that are best modeled using fully kinetic simulations, and pose challenges in terms of length scales, time scales, and complex particle interactions. We present simulations of TECs using two particle-in-cell software packages which use modern high-performance computing to meet the simulation challenges. Using WarpX, we demonstrate the simulation of a triode plasma TEC. Using Aleph, we present simulations of an ignited cesium plasma TEC, including a large set of multi-step ionization processes. The Cs plasma simulations also demonstrate shortcomings of approximate models used historically.