Near-field ion energy and species measurements of a 5-kW Hall thruster

A molecular beam mass spectrometer has been used to determine the ion compo sition and energy distribution of the P5 5-kW class laboratory Hall thruste r, A skimmer was used to obtain a sample of the plasma 10 cm downstream of the thruster exit plane, The thruster was operated at several discharge con ditions and rotated with respect to the sampling skimmer in order to determ ine ion-energy profiles at various plume angles. These measurements were co mpared to data taken 75 cm from the discharge plane to examine the evolutio n of the ion-energy profile and facility effects. Both ion-energy measureme nts and time-of-flight mass spectroscopy revealed evidence of singly, doubl y, triply, and quadruply charged xenon ions within the plume. Ion-energy di stributions were used to determine that the P5's magnetic field is oriented such that the plume has an overall inward focus, The ion-energy distributi ons taken 10 cm from the thruster had smaller full width at half maxima and less evidence of elastic collisions than those taken at 75 cm, Comparisons made with laser-induced fluorescence data showed good agreement.