Energy-tunable plasma dynamics and deposition in fluorinated energetic propellants for high-efficiency electric propulsion

The contamination and asymmetric deposition risks posed by ablation plasma plumes are critical concerns for the longevity and reliability of solid-propellant electric propulsion systems. This study systematically investigates the plasma dynamics and deposition behavior of Aluminum/Polytetrafluoroethylene (Al/PTFE) energetic composites in vacuum to address these challenges. The primary novelty lies in the combined application of time- and space-resolved optical emission spectroscopy with angularly resolved deposition mapping for Al/PTFE under vacuum. Results show that higher laser energy (0.9 J) enhances plasma ionization, producing over 50% more highly ionized species (Al III, F III) than 0.5 J. Electron temperature (0.16-0.46 eV) and density (6.18×10 16 -5.28×10 18 cm -3 ) profiles exhibit anisotropic spatiotemporal evolution. Deposition analysis after 500 pulses reveals a southeastward plasma deflection, concentrating 68% of the mass flux in the forward/lower quadrants, highlighting significant erosion risks in these orientations. Transparent substrates showed an 84% reduction in deposition thickness, suggesting the potential roles of thermophoretic sorting and Marangoni reflux. A persistent C>F>Al hierarchy in deposits was observed, consistent with carbon matrix dominance, potentially through catalytic graphitization. These findings provide quantitative insights for designing asymmetric thermal protection and contamination mitigation strategies in satellite propulsion systems.