Assessment of spectroscopic, real-time ion thruster grid erosion-rate measurements

Domonkos, Matthew T.; Stevens, Richard E.

doi:10.2514/6.2000-3815

Cited by 6 publications

(4 citation statements)

References 9 publications

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“…The assumption can be removed if the erosion rate is calibrated in situ. Several methods exist to achieve this, including sputtered targets and evaporating cells [41]. It is possible that combining SLA and LIF measurements could simplify the calibration process.…”

Section: Discussionmentioning

confidence: 99%

Measurement of 30-Centimeter Ion Thruster Discharge Cathode Erosion

Williams

Smith

Gallimore

2008

Journal of Propulsion and Power

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Relative erosion rates of the discharge cathode assembly of a 30-cm ion engine are measured using laser-induced fluorescence. Molybdenum and tungsten erosion products are interrogated downstream of the discharge cathode assembly during beam extraction. Erosion of the discharge cathode assembly is characterized for both keepered and unkeepered configurations. The erosion increases with both discharge current and voltage, and spatially resolved measurements agree with observed erosion patterns. Erosion rates are calculated using data from previous wear tests. Magnitudes and trends in the rates are correlated with both previous and subsequent wear tests. Laser-induced fluorescence is demonstrated to be a technique to measure relative internal erosion rates, and a path is identified for measuring absolute rates. Nomenclature= speed of light, 2:998 10 8 m=s E ij = energy of electronic state i with respect to state j, eV h = Plank's constant, 6:626 10 34 Js f oj = oscillator strength G = gaunt factor g i = degeneracy of state i g = Gaussian line shape, s I = intensity, W=m 2 I SAT = saturation intensity, W=m 2 J D = discharge current, A l = power-broadened line shape, s m C = discharge cathode flow rate, sccm m M = main flow rate, sccm n e = plasma density, cm 3 n i;j = density of state i or j, cm 3 n o = ground-state density, cm 3 P = thruster power, kW R oj = collisional population rate, cm 3 =s T e = electron temperature, eV TH = equivalent NSTAR throttle point V D = discharge voltage, V v = velocity, m=s = homogeneous relaxation rate, Hz = wavelength, m = frequency, Hz = cross section, m 2

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Section: Discussionmentioning

confidence: 99%

Measurement of 30-Centimeter Ion Thruster Discharge Cathode Erosion

Williams

Smith

Gallimore

2008

Journal of Propulsion and Power

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“…This assumption is based on the negligibly small triply charged ion current fraction observed in the beam of xenon ion thrusters operated at discharge voltages on the order of 25 V, as well as emission spectroscopic observations of an NSTAR discharge chamber during beam extraction. 20 Although not generally reported, the ratio of double-to-single ion current measured in the beam, neglecting higher charged states, is typically sufficient to assess efficiency losses due to multiply charged ions. 21 The yield equation was taken to be of the form recommended by Mantenieks.…”

Section: Modelmentioning

confidence: 99%

Wear Testing and Analysis of Ion Engine Discharge Cathode Keeper

Domonkos

Foster

Soulas

2005

Journal of Propulsion and Power

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“…When the ion thruster discharge current is a few hundred mA, it enters the arc discharge stage. Domonkos and Williams [15] measured the pulse phenomenon of annular discharge, and found that the pulse of annular discharge is particularly intense under the conditions of high current, low flow, and high voltage.…”

Section: Introductionmentioning

confidence: 99%

An equivalent model of discharge instability in the discharge chamber of Kaufman ion thruster

Tian¹,

Xie²,

Miao³

et al. 2022

Plasma Sci. Technol.

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The industrial application of the Kaufman ion thruster in its arc stage is limited owing to the instability of the discharge pulse. Presently, a complete prediction model that can predict the discharge pulse in the high-current stage does not exist. In this study, a complete prediction model for the pulse in the ion thruster is established using the zero-dimensional plasma discharge model and equivalent circuit model. The zero-dimensional plasma discharge model is used to obtain the corresponding plasma parameters by calculating the discharge current, voltage, and gas flow under actual working conditions. The input parameters of the equivalent circuit model are calculated using empirical formulae to acquire the estimated discharge waveforms. The pulse waveforms obtained using the model are found to be consistent with the experimental results. The model is used to evaluate the process of rapid changes in plasma density. Additionally, this model is employed to predict changes in the pulse waveforms when the volume of the discharge chamber and grid plate transmittance are changed.

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Assessment of spectroscopic, real-time ion thruster grid erosion-rate measurements

Cited by 6 publications

References 9 publications

Measurement of 30-Centimeter Ion Thruster Discharge Cathode Erosion

Measurement of 30-Centimeter Ion Thruster Discharge Cathode Erosion

Wear Testing and Analysis of Ion Engine Discharge Cathode Keeper

An equivalent model of discharge instability in the discharge chamber of Kaufman ion thruster

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