Far-Field Plume Measurements of a Nested-Channel Hall-Effect Thruster

Far-field plume measurements were performed on the X2 nested-channel Hall-effect thruster using a nude Faraday probe, retarding potential analyzer, and E×B probe. Data from these probes were used to examine the operating characteristics of the X2 with both channels operating simultaneously (dual-channel mode). For each operating condition in dual-channel mode, far-field measurements were also taken with each channel operating individually (single-channel mode) under the same applied magnetic field and cathode flow fraction. The results of the far-field measurements showed increased voltage utilization efficiency in dual-channel mode. Current utilization efficiency, divergence efficiency, charge utilization efficiency, and mass utilization efficiency did not show significant changes between the two operating modes. The far-field diagnostics also showed that the X2 operates similarly to a conventional Hall thruster when both channels are at the same discharge voltage. Small improvements in performance in the dual-channel mode were likely due to improved ion acceleration and reduced cathode coupling voltage.