Performance at High Current Densities of a Magnetically-Shielded Hall Thruster

Su, Leanne L.; Jorns, Benjamin

doi:10.2514/6.2021-3405

Cited by 8 publications

(8 citation statements)

References 31 publications

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“…This feature can be leveraged to generate higher thrust levels for a given cross-sectional area or to provide more fluence to a sputtering target. With that said, the available current density is not unlimited as there is some empirical evidence (see [11,12]) to suggest that with uncommonly high levels of current density, the plasma confinement in the E × B drift can be adversely impacted. This can decrease the overall efficiency of the device.…”

Section: Crossed-field Electrostatic Accelerationmentioning

confidence: 99%

Foundations of plasmas as ion sources

Jorns¹,

Lafleur²

2023

Plasma Sources Sci. Technol.

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An overview of low temperature, partially-magnetized ion sources is presented. This class of devices is broadly characterized by plasma densities below 1019 m-3, electron temperatures below 100 eV, and magnetic field strength tailored such that electrons are magnetized whereas ions are not. The overarching approach is pedagogical, targeting an audience that does not necessarily have an expertise in low temperature devices. A tutorial is presented on the basic physics of operation of common ion sources including an overview of common methods for plasma generation and acceleration. A review of typical diagnostics and common applications of these plasma sources is also presented. Special attention is given to applications in plasma propulsion and materials processing. This class of ion sources is then discussed in the context of the current state of the field, key technical and scientific challenges, and future prospects.

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Section: Crossed-field Electrostatic Accelerationmentioning

confidence: 99%

Foundations of plasmas as ion sources

Jorns¹,

Lafleur²

2023

Plasma Sources Sci. Technol.

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“…An empirical profile calibrated to work on one thruster will not work with a different thruster or even a different operating condition on the same thruster. For each new thruster or operational state, we instead must infer a new empirical profile from experimental measurements of the thruster [20,23]. This limits our ability to leverage empirical profiles for fully predictive simulations.…”

Section: Empirically Determining the Anomalous Collision Frequencymentioning

confidence: 99%

“…In contrast, probe-based methods to perform local measurements have shown in some cases to perturb the plasma properties [29]. All experimental measurements were collected while the H9 was operating at 300 V and 15 A on xenon [23,30].…”

Section: Thrustermentioning

confidence: 99%

“…As a last comment, we remark that while our goal remains to find self-consistent closures for predictive-fluid modeling, empirically-inferred transport profiles remain critical to thruster development and qualification. They have been leveraged, for example, for discovering new designs to that increase thruster lifetime [21] and for evaluating plasma conditions in regions of the discharge which are difficult to measure [23]. With this in mind, we have shown that closure models calibrated against empirical collision frequency datasets may play an important role in accelerating the calibration procedure for new thrusters and operating conditions.…”

Section: Implications For Future Closure Model Calibration and Discoverymentioning

confidence: 99%

“…These profiles are usually found by assuming the transport is static in time but varies spatially in the thruster. The profiles are then adjusted until key predictions of the code agree with experimental measurement [18][19][20][21][22][23]. This process yields useful insight into the state of the Hall thruster plasma in regions of the discharge that are not accessible by nonperturbative diagnostics, i.e.…”

Section: Introductionmentioning

confidence: 99%

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Challenges with the self-consistent implementation of closure models for anomalous electron transport in fluid simulations of Hall thrusters

Marks

Jorns

2023

Plasma Sources Sci. Technol.

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The performance of closure models for the anomalous electron transport when self-consistently implemented in a fluid model for a Hall effect thruster is investigated. This cross-field transport, which is orders of magnitude higher than classical collisional transport, is represented as an effective collision frequency. The proposed closure models relate this transport coefficient to local fluid properties of the plasma. Before implementation, the models are calibrated against values of the collision frequency inferred empirically from a 9-kW Hall thruster at 300 V and 15 A. It is found that even though closure models match the empirical collision frequency values, they diverge from these values when implemented self-consistently in a Hall thruster code. Possible drivers of this behavior are examined, including the role of non-linearity in the governing equations of the Hall thruster fluid model, artifacts from using time-averaged calibration data, and the non-uniqueness of the empirically-inferred collision frequencies. These results are discussed in the context of their implications for discovering and validating new closures necessary for enabling fully-predictive Hall thruster models. 

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A scaling methodology for high-power magnetically shielded Hall thrusters

Giammarinaro,

Marconcini,

Becatti

et al. 2023

J Electr Propuls

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The past two decades have seen an increasing interest in Hall thrusters in space propulsion, thanks to their favorable performance characteristics with respect to a wide variety of missions of current and future interest and to the significant extension in operational life potential achievable with magnetic shielding. Nevertheless, the physics underlying their behavior is complex and not yet fully understood, limiting the practical applications of models based on first principles due to their inability to self-consistently predict the device performance. Fortunately, modern Hall thrusters were developed through a lengthy process of gradual refinement, and thus they represent convenient reference devices to design new thrusters using appropriately defined scaling criteria. The objective of this work is to propose a new scaling methodology, especially intended for magnetically shielded high-power Hall thrusters. To this purpose, a novel phenomenological model for shielded thrusters is presented and discussed. This model includes free coefficients, whose values are chosen based on the agreement with the empirical data collected in a specially created high-power Hall thruster database. The proposed methodology features a new reference thruster and aims at keeping unchanged its main plasma intensive parameters in a scaling transformation. The possibility of creating performance maps at constant discharge power, which show how the scaling results vary with the channel dimensions, is also proposed as a preliminary design tool.

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Performance at High Current Densities of a Magnetically-Shielded Hall Thruster

Cited by 8 publications

References 31 publications

Foundations of plasmas as ion sources

Foundations of plasmas as ion sources

Challenges with the self-consistent implementation of closure models for anomalous electron transport in fluid simulations of Hall thrusters

A scaling methodology for high-power magnetically shielded Hall thrusters

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