Basic studies of a low density Hall current ion accelerator

Chubb, Donald L.; Seikel, G. R.

doi:10.2514/6.1966-76

Cited by 8 publications

(5 citation statements)

References 13 publications

(5 reference statements)

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“…All that remains in order to close the system of equations [Eqns. (3), (7) and (8)], is an energy equation or a prescription of the electron temperature in terms of the potential, i.e. T e (φ).…”

Section: Governing Equationsmentioning

confidence: 99%

“…This model explicitly introduces SEE effects to our formulation and, in combination with Eqns. (3), (7) and (8), allows us to study the effects of the walls on the extent of the acceleration zone.…”

Section: Prescription For T E (φ) Including Wall Propertiesmentioning

confidence: 99%

“…Under the above stated assumptions and definitions we obtain the following non-dimensional version of Eqns. (3), (7), (8) and (17).…”

Section: Non-dimensionalizationmentioning

confidence: 99%

“…Eq. (8)]. This will eventually lead to a crisis since further increase in electron density must be compensated by further increase in the electric field, dφ/dx, in order to maintain electron current continuity.…”

Section: Concluding Picturementioning

confidence: 99%

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Fundamental difference between the two variants of Hall thrusters - SPT and TAL

Choueiri¹

2001

37th Joint Propulsion Conference and Exhibit

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The fundamental difference between the two variants of Hall thrusters, the stationary plasma thruster (SPT) and the thruster with anode layer (TAL), is illustrated quantitatively using an analytical model that accounts for the effects of secondary electron emission (SEE) from the walls. The model includes a prescription for the quenching of the temperature of the electrons on their way to the anode which results from the enhanced electron energy losses to the wall that occur at, and upstream of, an axial location where the wall potential reverses from electronattracting to electron-repellent. For the higher SEE coefficient of an insulator wall (compared to that of a metallic one) this sign reversal occurs at a lower electron temperature and is shown to lead to a more extended acceleration region due to the resulting relaxation of the potential gradient required to balance the electron pressure gradient. By replacing the boron nitride walls (SPT) of an idealized Hall thruster with stainless steel (TAL), the acceleration zone is shown analytically to collapse to a region near the anode having an extent that is about eight times smaller than that for the SPT. The results are used to construct a detailed phenomenological picture of the fundamental difference between the two Hall thruster variants.

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Section: Governing Equationsmentioning

confidence: 99%

Section: Prescription For T E (φ) Including Wall Propertiesmentioning

confidence: 99%

“…Under the above stated assumptions and definitions we obtain the following non-dimensional version of Eqns. (3), (7), (8) and (17).…”

Section: Non-dimensionalizationmentioning

confidence: 99%

Section: Concluding Picturementioning

confidence: 99%

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Fundamental difference between the two variants of Hall thrusters - SPT and TAL

Choueiri¹

2001

37th Joint Propulsion Conference and Exhibit

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“…Hall thrusters were also attractive from the standpoint that since grids are not required to accelerate ions, they do not suffer from grid erosion. Interest in the Hall thruster waned in the early 1970s, however, because of budgetary cuts and because American researchers were never able to demonstrate that these engines could operate at thrust efficiencies near those achieved with ion thrusters [1,2,3]. As such, Hall thruster research essentially disappeared in the U.S. between 1972 and 1985.…”

Section: Introduction To the Hall Thrustermentioning

confidence: 99%

What We Have Learned By Studying The P5 Hall Thruster

Gallimore¹

2003

AIP Conference Proceedings

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The Hall thruster is an advanced spacecraft propulsion system that uses electrical power provided by the spacecraft to generate thrust by ionizing and accelerating ions to high velocities. While Hall thrusters have been tested in laboratories for nearly forty years and first flew in space some thirty years ago, little is known about the plasma within these devices. This lack of knowledge has led to the expensive trial-and-error approach practiced in Hall thruster development over the years. The difficulty in collecting interior plasma data stems from the intense heat flux a probe receives. While optical measurements can give some information about the plasma, probes provide data about the plasma that are not accessible with optical approaches. Discharge channel plasma data are vital for extending our understanding of Hall thruster physical processes, for validating thruster models, and for developing advanced, next-generation engines for high DV missions. The paper summarizes the results of research aimed at using probes to characterize the internal plasma structure of a laboratory Hall thruster developed specifically for this purpose. Internal plasma parameter measurements were accomplished by using the unique High-speed Axial Reciprocating Probe (HARP) system, which enabled, for the first time, the insertion and removal of probes from the Hall thruster discharge channel while minimizing perturbation to thruster operation. The system was used with an emissive probe to map plasma potential, and a double Langmuir probe to map electron temperature and ion number density. Thruster perturbation, determined by monitoring discharge current, was less than 10% for the majority of measurements

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Near- and Far-Field Characterization of Stationary Plasma Thruster Plumes

Gallimore

2001

Journal of Spacecraft and Rockets

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A comprehensive investigation of Hall thruster plume plasma ion energy distribution functions and ion charge state has been made on both ight-and laboratory-model engines. An energy analyzer, mass spectrometer, and E £ B probe were used to characterize Hall thruster plume ions. The results of this investigation show that the distribution function of the ion beam exhibits both Maxwellian and Druyvesteyn traits and that the Hall thruster plume contains a nontrivial amount of energetic, multiply charged particles that must be accounted for in modeling the erosion rate of solar array cover glass and interconnect material. Detection of these multiply charged ions by energy analyzers has been hampered in the past by charge exchange and elastic collisions. The high-energy tail seen in numerous energy analyzer data is thought to result from charge exchange and elastic collisions between singly and multiply charged ions and neutrals. The role of facility pressure was also investigated and was found to have an in uence mainly on the width of the ion energy distribution function. This pressure broadening is caused by elastic collisions between beam ions and background chamber gas particles. Nomenclaturecollector current, A n i = ion number density, m ¡3 q = elementary charge, C q I = charge state of ion r = position vector, m t = time, s u i = ion speed, m/s V i = beam ion acceleration potential, V v = ion velocity vector, m/s

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Basic studies of a low density Hall current ion accelerator

Cited by 8 publications

References 13 publications

Fundamental difference between the two variants of Hall thrusters - SPT and TAL

Fundamental difference between the two variants of Hall thrusters - SPT and TAL

What We Have Learned By Studying The P5 Hall Thruster

Near- and Far-Field Characterization of Stationary Plasma Thruster Plumes

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