Electrostatic/magnetic ion acceleration through a slowly diverging magnetic nozzle between a ring anode and an on-axis hollow cathode

Sasoh, Akihiro; Mizutani, Kana; Iwakawa, Akira

doi:10.1063/1.4985380

Cited by 12 publications

(18 citation statements)

References 18 publications

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“…They recognised that a lack of available solar power has historically prevented AF-MPDTs from being considered for spaceflight operation, in spite of the fact that they had shown promise for near-to mid-term propulsion requirements [8] [56]. They decided to implement a hybrid approach, whereby a thruster contains elements of both applied-field electromagnetic thrusters, and of gridless electrostatic thrusters [71]. The studies thus far have indicated that there is a wealth of new research to conduct on this hybrid approach [71]- [76].…”

Section: Resolving the Conundrum: Combining Forcesmentioning

confidence: 99%

“…They decided to implement a hybrid approach, whereby a thruster contains elements of both applied-field electromagnetic thrusters, and of gridless electrostatic thrusters [71]. The studies thus far have indicated that there is a wealth of new research to conduct on this hybrid approach [71]- [76]. Some key findings have been increased operational efficiency at low power over an AF-MPDT, increased thrust density over HETs, and results of efficiency improvement with different magnetic field topologies.…”

Section: Resolving the Conundrum: Combining Forcesmentioning

confidence: 99%

“…Therefore, the thrust force is transferred to the thruster via the component responsible for holding the electrons in place: the magnetic field. At the University of Nagoya, our partner institution for this study, Sasoh et al reduced the thrust to [71]:…”

Section: Adding An Electrostatic Thrust Component: the Cc-est21mentioning

confidence: 99%

“…Within the context of this study, the available facility for thruster is the University of Nagoya's vacuum chamber, thrust stand and plasma diagnostic tools. The vacuum chamber comprises a cylinder with an inner length of 4 m and a diameter of 2 m. The thrust stand is a hanging pendulum stand designed to operate in the 100 mN range [71]. The plasma diagnostic tools consist of a Langmuir triple probe, a guarded ring Faraday probe, and a retarding-potential analyser [140].…”

Section: Thruster Experimentsmentioning

confidence: 99%

“…Figure from [87], reproduced with permission. The thrust balance at the University of Nagoya is a hanging pendulum type thrust balance [71].…”

Section: Thrust Measurementmentioning

confidence: 99%

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A Central-Cathode Electrostatic Thruster Featuring a High-Temperature Superconducting Applied Field Module

Acheson

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In recent decades, advances in electric propulsion have enabled the development of novel mission designs for space exploration. However, future deep space mission payloads of unprecedented mass will require advances in high thrust, high specific impulse propulsion. To achieve higher thrust density than traditional ion thrusters or Hall effect thrusters, novel designs for central-cathode electrostatic thrusters (CC-ESTs) and applied field magnetoplasmadynamic thrusters incorporate an applied magnetic field module which is used to accelerate plasma. The high thrust density of such designs makes them suitable candidates for further research and development for space deployment.Crucial performance metrics of such thrusters have been shown to increase as the applied magnetic field increases, and high temperature superconducting (HTS) magnets show promise as low-power, high applied field modules. Both the strength and the profile of the applied magnetic field are closely tied to thruster performance. This raises the question- which magnetic fields improve thruster performance and why?In this thesis, the impact of the magnetic field strength and profile on the performance of a plasma thruster is investigated. Numerical modelling of a central-cathode electrostatic thruster (CC-EST) was performed with particular regard to the detachment of plasma from magnetic field lines. This modelling was conducted alongside an experimental campaign to manufacture and integrate a high temperature superconducting applied field module with a CC-EST to characterise the HTS CC-EST performance. CC-EST performance was measured at central bore fields exceeding 1 T and with two different magnetic field profiles. These efforts have led to a novel understanding of the scaling of performance parameters in CC-EST with magnetic field, and how the performance of the thruster might be tailored to a specific application.

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Section: Resolving the Conundrum: Combining Forcesmentioning

confidence: 99%

Section: Resolving the Conundrum: Combining Forcesmentioning

confidence: 99%

Section: Adding An Electrostatic Thrust Component: the Cc-est21mentioning

confidence: 99%

Section: Thruster Experimentsmentioning

confidence: 99%

“…Figure from [87], reproduced with permission. The thrust balance at the University of Nagoya is a hanging pendulum type thrust balance [71].…”

Section: Thrust Measurementmentioning

confidence: 99%

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A Central-Cathode Electrostatic Thruster Featuring a High-Temperature Superconducting Applied Field Module

Acheson

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A theoretical thrust density limit for Hall thrusters

2023

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Hall Thrusters typically operate at thrust densities on the order of 10 N/m$$^2$$ 2 , which appear to be orders of magnitude below the thrust density limits suggested in previous literature. These limits have been considered here and each component of thrust density is analyzed to demonstrate the relative contribution to the total thrust density. Dependencies of the thrust density limits upon the thruster geometry, electron mobility, and the applied magnetic field are revealed and compared with experimental measurements of thrust density. This analysis reveals that with conventional applied magnetic field strengths, Hall thruster thrust density appears to be on the order of 1000 N/m$$^2$$ 2 . It is shown that this limit can be further increased through higher applied magnetic fields, applied voltage, and suppression of anomalous electron transport. This suggests Hall thrusters can be made much more compact and operated at higher power densities, given improvements to the thermal management and materials.

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Operational demonstration and experimental characterisation of a central cathode electrostatic thruster equipped with a high temperature superconducting magnet

Acheson,

Glowacki,

Nakano

et al. 2023

J Electr Propuls

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Interplanetary transport of payloads of unprecedented mass, as envisaged beyond the lunar gateway, will require thrusters with high specific impulse as well as high thrust. To achieve this, innovations in propulsion are critical. Many classes of electric thruster utilise a magnetic applied field module to accelerate charged particles. Magnetoplasmadynamic thrusters exhibit improved performance with increasing field, at least up to the limit of around 0.5 T able to be provided by permanent magnets or copper electromagnets. However, superconducting magnets can generate much stronger magnetic fields. In this study, we utilised a space-relevant cryocooled high temperature superconducting magnet as the applied field module for a central cathode electrostatic thruster (CC-EST). A convex anode enabled ignition at high magnetic fields, and in this configuration the thruster’s performance was characterised in the power range of 1 kW to 2.5 kW and at steady applied fields ranging from 0.6 T to 0.8 T, representing a significant advance in achievable field strength. In combination, these operating parameters enabled the achievement of a magnet-inclusive thruster efficiency of 19%, while the cryocooled magnet was demonstrated to be thermally stable in the presence of the kW-scale plasma, demonstrating the viability of such a design for space flight applications.

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Electrostatic/magnetic ion acceleration through a slowly diverging magnetic nozzle between a ring anode and an on-axis hollow cathode

Cited by 12 publications

References 18 publications

A Central-Cathode Electrostatic Thruster Featuring a High-Temperature Superconducting Applied Field Module

A Central-Cathode Electrostatic Thruster Featuring a High-Temperature Superconducting Applied Field Module

A theoretical thrust density limit for Hall thrusters

Operational demonstration and experimental characterisation of a central cathode electrostatic thruster equipped with a high temperature superconducting magnet

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