Studies of Non-Conventional Configuration Closed Electron Drift Thrusters

Raitses, Y.; Staack, David; Smirnov, A.; Litvak, A.; Dorf, L.; Graves, T. P.; Fisch, Nathaniel J.

doi:10.2172/788220

Cited by 3 publications

(11 citation statements)

References 5 publications

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“…This may indicate a downstream migration of the acceleration region, with resulting increase in plume divergence (see also Fig. 7) as discussed in [5]. For both NS2 and TS1 the best results were obtained with cathode bias, and motivated investigation of case TS1B.…”

Section: B Baseline Performance and Effect Of Magnetic Fieldmentioning

confidence: 82%

“…Diamant et al [13] describes our first attempt to obtain independent confirmation of the results presented in [1,[3][4][5][6]. Nonemissive graphite electrodes were used, and electromagnet currents were held constant.…”

mentioning

confidence: 86%

“…To eliminate the possibility that material sputtered from the exposed outer magnetic pole (low carbon steel) was entering the discharge channel and influencing plume divergence, the outer pole was coated with BN. This coating was not present in [1,[3][4][5][6]. Figure 7 shows that for cases NS1, NS2, NS3, and TS1 the largest plume divergence reduction with the BN coating was only 2 deg.…”

Section: B Baseline Performance and Effect Of Magnetic Fieldmentioning

confidence: 99%

“…To reduce electrode sputtering, and because favorable results were obtained with nonemissive electrodes, a carbon-carbon-fiber electrode was tested on the channel inside diameter near the thruster exit [5]. Plume half-angle reductions of approximately 5 deg were measured with the electrode biased to cathode potential or floating.…”

mentioning

confidence: 99%

“…Because the magnetic field geometry exerts a strong influence on the plume profile [6,14,15], and because different channel configurations may require different optimum values of the magnetic field, in this study the magnetic field was adjusted for minimum plume divergence (except as noted in Sec. III.B) while testing several more electrode geometries similar to those investigated in [1,[3][4][5][6].…”

mentioning

confidence: 99%

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Segmented Electrode Hall Thruster

Diamant¹,

Pollard²,

Cohen³

et al. 2006

Journal of Propulsion and Power

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Thrust, thrust efficiency, and plume divergence were measured for a 9 cm diam laboratory model Hall thruster with segmented electrodes in the discharge channel. Several geometries with graphite nonemissive electrodes, and one with a tungsten emissive electrode were tested and compared to a baseline configuration with all electrodes replaced by boron nitride segments. To within measurement uncertainty, thrust and thrust efficiency were unaffected by insertion of electrodes, with the exception of reduced efficiency for a configuration which resulted in a 20% increase in discharge current. Maximum plume half-angle reductions of 4 deg were obtained with emissive and nonemissive electrodes.

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Section: B Baseline Performance and Effect Of Magnetic Fieldmentioning

confidence: 82%

mentioning

confidence: 86%

Section: B Baseline Performance and Effect Of Magnetic Fieldmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Segmented Electrode Hall Thruster

Diamant¹,

Pollard²,

Cohen³

et al. 2006

Journal of Propulsion and Power

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Plasma flow and plasma–wall transition in Hall thruster channel

2001

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In this paper a model of the quasineutral plasma and the transition between the plasma and the dielectric wall in a Hall thruster channel is developed. The plasma is considered using a two-dimensional hydrodynamic approximation while the sheath in front of the dielectric surface is considered to be one dimensional and collisionless. The dielectric wall effect is taken into account by introducing an effective coefficient of the secondary electron emission ͑SEE͒, s. In order to develop a self-consistent model, the boundary parameters at the sheath edge ͑ion velocity and electric field͒ are obtained from the two-dimensional plasma bulk model. In the considered condition, i.e., ion temperature much smaller than that of electrons and significant ion acceleration in the axial direction, the presheath scale length becomes comparable to the channel width so that the plasma channel becomes an effective presheath. It is found that the radial ion velocity component at the plasma-sheath interface varies along the thruster channel from about 0.5C s ͑C s is the Bohm velocity͒ near the anode up to the Bohm velocity near the exit plane dependent on the SEE coefficient. In addition, the secondary electron emission significantly affects the electron temperature distribution along the channel. For instance in the case of sϭ0.95, the electron temperature peaks at about 16 eV, while in the case of sϭ0.8 it peaks at about 30 eV. The predicted electron temperature is close to that measured experimentally. The model predictions of the dependence of the current-voltage characteristic of the EϫB discharge on the SEE coefficient are found to be consistent with experiment.

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