On-line Monitoring of Carbon Erosion Products in Krypton Hall Thrusters Based on Optical Emission Spectroscopy Method and Development of a Triple-Line Ratio Energy Difference Decoupling Model

With the development of magnetic shielding Hall thruster technology, the erosion of key components in Hall thrusters has gradually shifted from ceramic channels to magnetic poles. The erosion of magnetic poles generates carbon atoms that adsorb backflowing electrons, entering the thruster interior and depositing as contaminants on electrode and channel wall surfaces. These contaminants may detach due to temperature differences, potentially causing sparking or even shutdown of the Hall thruster, severely threatening its reliability.
This study focuses on a krypton Hall thruster, conducting online monitoring of carbon as an erosion product from the magnetic poles based on optical emission spectroscopy (OES) method. A triple-line ratio energy difference decoupling model suitable for krypton is developed to establish a direct mapping relationship between the line ratio of krypton-carbon emission lines and the concentration of carbon atoms. This approach ensures that the concentration of carbon atoms depends solely on the composite line ratio, eliminating reliance on excitation threshold energy and electron temperature in traditional spectral quantification models, thereby improving the stability and reliability of OES method.