Near-Plume Laser-Induced Fluorescence Velocity Measurements of a Medium Power Hall Thruster

摘要

This work presents the near exit plane velocity field of a 600WHall thruster at a single operating condition with an300 V anode potential. The xenon ion propellant velocities were measured using laser-induced fluorescence of then5du00014u00027=2 u0003 6pu00013u00025=2 excited state xenon ionic transition at 834.72 nm. Ion velocities were interrogated from thenacceleration channel exit plane to a distance 100 mm from the exit plane (1.6 exit plane diameters). Both axial andnradial velocities were directly measured. A nearly uniform axial velocity profile of approximately 17; 000 m=sn(197 eV) was measured at the acceleration channel center on the exit plane. The maximum axial velocity wasnmeasured 100 mm from the exit plane at 19; 800 m=s (267 eV). In conjunction with the coaxial symmetry of thenthruster, radial velocity measurements were used to determine the divergence of the plume, as well as to determinenazimuthal velocities in several regions proximate to the exit plane. The 475 m=s mean azimuthal velocity wasnmeasured 5mmfromthe exit plane. Fromthis value, it was possible to estimate amaximumthruster-induced torquenof 3:2 u0004 10u00035nNm. Because of the divergence and convergence of the coaxial ion flow, distinct ion populations werenobserved to interact in the central core of the near plume.Thiswas apparent inmeasurement volumeswheremultiplenradial and axial velocity components were measured. These regions also typically correspond with the brightestnportions of the visible plume.