Seminar DPPT: Jan Skácel

We cordially invite you to a Department of Plasma Physics and Technology seminary lecture. The speaker is František Zažímal, a Ph.D. candidate at the Plasma Diagnostics and Modelling research group, DPPT and CEPLANT center.

Mgr. Jan Skácel – Development of Kinetic-based Boundary Conditions for the Electrodes of the NASA Ames Arc Heater

The NASA Ames arc heater operates by heating a working gas to temperatures of ~10,000 K using a DC arc sustained between two copper electrodes, which is used for hypersonic re-entry study. Recent fluid simulations captured the main discharge features but failed to accurately represent arc attachment to the electrodes, which determines erosion and further failure.

In this work, we investigate the thin electrode attachment layer using 1D particle-based kinetic simulations, allowing us to access key processes such as electrode evaporation, thermionic emission, and gas ionization and excitation. We find that a large voltage drop can develop in the cathode layer, which also serves as the main ionization source sustaining the arc. Metal vapor from the electrode is also shown to strongly influence the discharge due to its low excitation energy, enhancing electron-heavy particle energy exchange. Finally, we propose a strategy for using these small-scale simulations to improve boundary conditions in full arc fluid models.