Hall-type low- and mean-power thrusters output parameters

Belikov, M.; Gorshkov, O. A.; Ризаханов, Р. Н.; Shagaida, A. A.; Khartov, S. A.

doi:10.2514/6.1999-2571

Cited by 7 publications

(6 citation statements)

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“…A plasma lens configuration preferentially focuses plasma away from the walls, which improves performance and thermal margin, decreases plume divergence, and increases lifetime. 29,32,33 This focusing effect is possible because, to an accuracy on the order of the electron temperature, magnetic field lines form equipotentials of the applied voltage. 34 The argument that magnetic field lines influence the shape of the electric field has proven to be an invaluable tool in Hall thruster design for decades.…”

Section: Hall Thrustermentioning

confidence: 99%

High-Specific Impulse Hall Thrusters, Part 1: Influence of Current Density and Magnetic Field

Hofer¹,

Jankovsky

Gallimore

2006

Journal of Propulsion and Power

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A laboratory-model Hall thruster with a magnetic circuit designed for high-specific impulse (2000-3000 s) was evaluated to determine how current density and magnetic field affect thruster operation. Results have shown for the first time that a minimum current density and optimum magnetic field shape exist at which efficiency will monotonically increase with specific impulse. At the nominal mass flow rate of 10 mg/s and between discharge voltages of 300 and 1000 V, total specific impulse and total efficiency ranged from 1600 to 3400 s and 51 to 61%, respectively. Comparison with a similar thruster showed how efficiency can be optimized for specific impulse by varying the shape of the magnetic field. Plume divergence decreased from a maximum of 48 deg at 400 V to a minimum of 35 deg at 1000 V, but increased between 300 and 400 V as the likely result of a large increase in discharge current oscillations. The breathing-mode frequency continuously increased with voltage, from 14.5 kHz at 300 V to 22 kHz at 1000 V, in contrast to other Hall thrusters where a sharp decrease of the breathing-mode frequency was found to coincide with increasing electron current and decreasing efficiency. These findings suggest that efficient, high-specific impulse operation was enabled through the regulation of the electron current with the applied magnetic field. . Associate Fellow AIAA. η t = total efficiency θ = azimuthal coordinate direction ∇ z B r = axial gradient of the centerline radial magnetic field

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Section: Hall Thrustermentioning

confidence: 99%

High-Specific Impulse Hall Thrusters, Part 1: Influence of Current Density and Magnetic Field

Hofer¹,

Jankovsky

Gallimore

2006

Journal of Propulsion and Power

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“…The NASA-173M magnetic circuit employs what is commonly referred to as a plasma lens, [9][10][11][12][13] established by a set of inner and outer coils and pole pieces. In a plasma lens, the field line curvature focuses ions on the channel centerline, which has been shown to extend the focal length of the plume to distances of several thruster diameters.…”

Section: Plasma Lens Focusingmentioning

confidence: 99%

The Role of Magnetic Field Topography in Improving the Performance of a High Voltage Hall Thruster

Hofer

Gallimore²

2002

38th AIAA/ASME/SAE/ASEE Joint Propulsion Conference &Amp;amp; Exhibit

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Investigations of high-voltage Hall thrusters have indicated a peak in the efficiency versus voltage characteristic that limited the maximum efficiency to specific impulses of less than 3000 s. This peak is believed to be primarily a trait of modern magnetic field design, which is optimized for discharge voltages of 300 V. The NASA-173M has been operated at 300-1000 V and 5 mg/s to investigate whether performance improvements could be realized through in situ variation of the magnetic field topography through the use of an auxiliary trim coil. Without the trim coil, a peak in the efficiency characteristic was observed at 600 V. The results with the trim coil energized indicate there is always some performance benefit to altering the magnetic field topography. Above 400 V, efficiencies were maintained at >50% and above 900 V, specific impulses >3000 s were demonstrated while using the trim coil. The largest gains in performance were observed at 1000 V, where the thrust, specific impulse, and efficiency improved by 10 mN, 200 s, and 5.5%, respectively, to 165 mN, 3360 s, and 51.5%. The results demonstrate that the peak in the efficiency characteristic observed without the trim coil can be mitigated when the magnetic field topography is tailored for high-voltage operation. Analysis of the magnetic field from numerical simulations has identified several important factors contributing to the performance benefits with trim coil operation.

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“…port, heating, erosion, and plume divergence [13], [14] and, therefore, reduced efficiency, specific impulse, and life. With a few exceptions (BHT-200 [8], KM-37 [13], SPT X-40 [14], and SPT-20M6.1 [15]), anode efficiencies (i.e., thrust efficiency calculated without accounting for propellant flow to a cathode) for annular Hall thrusters operating below 200 W are less than 40%.…”

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confidence: 99%

Ionization, Plume Properties, and Performance of Cylindrical Hall Thrusters

Diamant

Pollard

Raitses

et al. 2010

IEEE Trans. Plasma Sci.

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It is shown experimentally that the cylindrical Hall thruster (CHT) produces a highly ionized plasma flow with mass utilization efficiencies greater than 100% due to generation of multicharged ions. For the CHT employing geometries with and without a short annular section, used to enhance ionization, plume divergence reductions of approximately 25% were demonstrated by running a cathode-keeper discharge along with the main cathode-anode discharge. Thruster anode efficiencies varied from approximately 15% to 35% over input powers from 70 to 220 W. A 2-A keeper discharge resulted in an approximately 20% increase in anode specific impulse for both geometries, and the specific impulse for the case of no annular section was, on average, 13% higher than that with the annular section. The multicharged ion fraction increased with keeper current, and the quantity of channel erosion products in the plume was correlated with that of multicharged ions.

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Hall-type low- and mean-power thrusters output parameters

Cited by 7 publications

References 0 publications

High-Specific Impulse Hall Thrusters, Part 1: Influence of Current Density and Magnetic Field

High-Specific Impulse Hall Thrusters, Part 1: Influence of Current Density and Magnetic Field

The Role of Magnetic Field Topography in Improving the Performance of a High Voltage Hall Thruster

Ionization, Plume Properties, and Performance of Cylindrical Hall Thrusters

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