README.md

2026LZZ

Codex/ChatGPT (July 2026)

Summary

The authors use long-duration, instability-resolving three-dimensional particle-in-cell simulations to map anomalous cross-field electron transport in a Hall thruster. The model combines a realistic magnetic field, xenon ionization, continuum neutral evolution, dielectric charging, secondary-electron emission, and open plume outflow. Time and azimuthal averaging of $\langle n_eE_y\rangle$ over 200 samples reveals two persistent transport bands adjacent to the inner and outer walls near the downstream channel and exit, with the inner-wall pathway generally stronger. Conducting, ceramic-with-emission, and open-outflow boundaries alter pathway strength and downstream extension but not its topology. Dominant electron-drift-instability wavelengths are about $1,\mathrm{mm}$; fitted in-channel and near-exit phase speeds of $5.20$ and $6.02,\mathrm{mm}/\mu\mathrm{s}$ closely match local ion-acoustic speeds. Doubling the $5,\mathrm{ps}$ timestep changes the spectrum but preserves the averaged pathway. Fine-scale amplitudes and spectra are less secure than the large-scale topology because the baseline grid does not resolve the Debye length everywhere.

Contributions

1. Resolved net instability-driven transport as two wall-adjacent pathways rather than a uniform flux.
2. Combined realistic magnetics, ionization, neutral evolution, wall charging, emission, and open outflow in one 3D model.
3. Demonstrated that the near-wall topology persists across different wall and plume closures.
4. Linked the averaged pathways to millimeter-scale modes with ion-acoustic-scale phase speeds.
5. Distinguished robust transport topology from timestep- and grid-sensitive spectral details.