Test particle study of electron transport driven by ECDI induced waves in a Hall thruster

Electron transport in a Hall thruster is investigated at the test particle level using prescribed electric fields derived from the electron cyclotron drift instability (ECDI) resolving three dimensional particle-in-cell (PIC) simulation. Four primary electric field configurations are considered: static averaged field, full PIC field, proper orthogonal decomposition (POD) reconstructed field, and a simplified analytical Ey field. Two additional control cases, the magnetic-field-only case and the denoised PIC field, are also included. Transport statistics show that the averaged field produces only weak axial cross field transport. In contrast, the full PIC field produces clear fluctuation driven transport, characterized by pronounced negative axial displacement, enhanced channel entry, finite channel residence, particle energization, and appreciable anode directed loss. POD analysis shows that the transport relevant ECDI electric field structures are distributed over multiple coupled modes, and that a moderate truncation order of approximately $20$ modes is sufficient to recover the main transport signatures for the diagnostics examined. The analytical Ey model, which provides a simplified, data-informed representation of the PIC azimuthal field, is used to assess the contribution of azimuthal fluctuations to axial electron transport and to isolate the effects of their amplitude and frequency.