Hall thruster plume divergence angle assessment method based on image processing

•A new plume divergence angle image assessment method is proposed.•This method has advantages of being fast, simple and a proper accuracy.•This method is a competitive method in a short-term timescale measurement.

A kind of plume divergence angle assessment method in Hall thrusters is proposed based on image processing. The detail assessment method and probable error is described and discussed. Comparing with the probe measurement method, this assessment method has advantages of being fast, simple and properly accurate. These advantages show that it is a competitive method to analyze dynamic characteristics of plume divergences in a low frequency oscillation time scale.