High-speed planar plasma density measurements in a hall thruster plume

Summary form only given. The unsteady behavior of a Hall effect thruster discharge is investigated via two-dimensional, time-resolved optical (109,500 frames-per-second) and plasma measurements (100 kHz). Large amplitude unsteady ionization "breathing-mode" fluctuations at 18.4 kHz are observed in the near- and far-field plume electron density, optical intensity, and discharge current of a 200-V, 2-A plasma plume generated by a 600-W Hall effect thruster. A specially designed High-speed Dual Langmuir Probe (HDLP) system is used to perform time-resolved measurements of the discharged plasma density and temperature in a planar grid of 352 elements measuring 0.31 m by 0.5 m. Using methods of Fourier analysis, contour-map movies with a 10-??s framerate of the plasma properties are created and presented with corresponding optical images taken with a high-speed camera. Discrete turbulent bursts of plasma are tracked as the thruster exhales breaths of ionized propellant at rates in excess of 12 km/s. These temporally-resolved measurements offer rare insight into the dynamic physics of thruster operation through unprecedented, detailed visualizations of the plasma density flow-field temporal evolution and structure.