Grid Erosion Modeling of the Next Ion Thruster Optics

Emhoff, Jerold; Boyd, Iain D.

doi:10.2514/6.2003-4868

Cited by 19 publications

(8 citation statements)

References 4 publications

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“…This model has been used previously to predict electron backstreaming. In previous simulations, 12 the backstreaming limit was reached after approximately the same thruster operating time. Results for a three-dimensional model 7 predict thruster failure much sooner, after a propellant throughput of 625 kg.…”

Section: Discussionmentioning

confidence: 74%

Modeling of Total Thruster Performance for NASA's Evolutionary Xenon Thruster Ion Optics

Emhoff

Boyd

2006

Journal of Propulsion and Power

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An axisymmetric ion-optics model is applied to NASA's Evolutionary Xenon Thruster (NEXT) ion engine. The model is used to simulate the performance of the entire thruster by modeling several apertures at varying radii on the thruster face and integrating the results. The integrated results are compared to experimentally measured data for the NEXT thruster, showing good agreement in most areas. The primary area of discrepancy is in the accelerator grid current, although erosion results suggest that the measured current is unaccountably high. The model is also used to estimate the life of the thruster before the onset of electron backstreaming. Three separate methods are applied, and each predicts thruster failure after approximately 40,000 hours of operation or 845 kg of xenon throughput.

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Section: Discussionmentioning

confidence: 74%

Modeling of Total Thruster Performance for NASA's Evolutionary Xenon Thruster Ion Optics

Emhoff

Boyd

2006

Journal of Propulsion and Power

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“…The nature of plasma flow in ion optics renders particle-in-cell (PIC) [1] based models, which simulate a collisionless plasma by solving plasma particle trajectories, space charge, and the electric field self-consistently as the most appropriate approach for ion optics modeling. Numerous PIC-based ion optics simulation codes have been developed (see, for example, [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] and references therein). Whereas earlier studies have focused on the physics of a single beamlet, recent studies have also begun to use ion optics models to predict the behavior of entire ion optics.…”

mentioning

confidence: 99%

Whole Ion Optics Gridlet Simulations Using a Hybrid-Grid Immersed-Finite-Element Particle-in-Cell Code

Kafafy

Wang

2007

Journal of Propulsion and Power

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A new model is developed for three-dimensional global simulations of plasma flow in an entire subscale ion optics. This model explicitly includes apertures located near the edge of the grid surface and fully accounts for the effects of multiple ion beamlets and geometric asymmetry. This model is based on a new algorithm, the streamline hybrid-grid immersed-finite-element particle-in-cell. This algorithm is capable of achieving the same accuracy as an unstructured body-fit mesh-based particle-in-cell with a faster computational speed. Simulation results are presented to understand the plasma sheath upstream of the screen grid, direct impingement of beam ions, the crossover limit, the perveance limit, and the electron backstreaming onset. Nomenclature e = electron charge F = force vector I = current k = Boltzmann constant m = mass q = charge T = temperature t = time v = velocity vector x = position vector = IFE mesh stretching parameter 0 = electric permittivity of vacuum D = Debye length = charge density = electrostatic potential Subscripts a = accelerator grid b= beamlet cc = center-to-center e = electron g = gap between ion optics grids i = ion, or impingement s = screen grid w = grid wall 0 = upstream plasma condition 1 = downstream plasma condition

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“…For example, a PIC-DSMC grid optics code continues to undergo development and is being used to help design NASA's NEXT ion thruster. Based on modeling results, a set of Thick Aperture Optics (TAG) has been selected [21,22] as a design for future testing. A detailed PIC-DSMC model is also being applied to describe the plume from the T6 hollow cathode and compared with experimental measurements [23].…”

Section: Research At the University Of Michiganmentioning

confidence: 99%

Overview of Electric Propulsion Research in Academia

Blandino

Gatsonis

Cappelli

et al. 2003

39th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit

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An overview is presented of electric propulsion research carried out in U.S. academic institutions. Universities in the U.S. are engaged in a wide range of research, varying from fundamental studies in micro thruster concepts, to future flight involving magneto plasma sails. II. PROGRAM HIGHLIGHTS A. Research at Worcester Polytechnic Institute Research at the Worcester Polytechnic Institute (WPI) falls under the programs headed by Professors John Blandino and Nikolaos Gatsonis. Blandino's research is largely focused on the study of colloid thrusters for small satellite propulsion, and in the development of novel, earth-orbiting spacecraft formations. The investigation of colloid thruster technology is a continuing activity with a

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Grid Erosion Modeling of the Next Ion Thruster Optics

Cited by 19 publications

References 4 publications

Modeling of Total Thruster Performance for NASA's Evolutionary Xenon Thruster Ion Optics

Modeling of Total Thruster Performance for NASA's Evolutionary Xenon Thruster Ion Optics

Whole Ion Optics Gridlet Simulations Using a Hybrid-Grid Immersed-Finite-Element Particle-in-Cell Code

Overview of Electric Propulsion Research in Academia

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