A photographic method for in-orbit measurement of electron temperature distribution in the plume of Hall thrusters

This paper presents a method for measuring the plasma parameters of a Hall thruster plume based on image diagnostics. A digital camera obtains the plume image, and the RGB (red, green, blue) data extracted from the plume image are related to the light intensity information of different spectral lines. A photographic method for obtaining the electron temperature distribution in the Hall thruster plume is established by using RGB data based on the collisional-radiative (CR) model. The results from this photographic method were compared with published results from measurements made with a Langmuir probe and simulated results. The trends of the electron temperature distribution were similar to those results. The limitations and application of the photographic method, which could ensure that it is suitable for diagnosing the plasma parameters of the in-orbit Hall thruster plume, are also discussed.