Effect of magnetic and physical nozzles on plasma thruster performance

Takahashi, Kazunori; Charles, Christine; Boswell, Roderick; Andõ, Akira

doi:10.1088/0963-0252/23/4/044004

Cited by 47 publications

(35 citation statements)

References 38 publications

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“…5, where the typical displacement signal of the thrust stand for the steady-state plasma production can be found in Ref. 22 are the fitting parameters. It is found that the measured values without the target is slightly higher than that with the target; it is consistent with the model 24 predicting the increase in the thrust along the axis.…”

Section: Resultsmentioning

confidence: 99%

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Measurement of plasma momentum exerted on target by a small helicon plasma thruster and comparison with direct thrust measurement

Takahashi

Komuro

Andõ

2015

Review of Scientific Instruments

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Momentum, i.e., force, exerted from a small helicon plasma thruster to a target plate is measured simultaneously with a direct thrust measurement using a thrust balance. The calibration coefficient relating a target displacement to a steady-state force is obtained by supplying a dc to a calibration coil mounted on the target, where a force acting to a small permanent magnet located near the coil is directly measured by using a load cell. As the force exerted by the plasma flow to the target plate is in good agreement with the directly measured thrust, the validity of the target technique is demonstrated under the present operating conditions, where the thruster is operated in steady-state. Furthermore, a calibration coefficient relating a swing amplitude of the target to an impulse bit is also obtained by pulsing the calibration coil current. The force exerted by the pulsed plasma, which is estimated from the measured impulse bit and the pulse width, is also in good agreement with that obtained for the steady-state operation; hence, the thrust assessment of the helicon plasma thruster by the target is validated for both the steady-state and pulsed operations.

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Section: Resultsmentioning

confidence: 99%

“…22. Briefly, the equilibrium displacement D b of the thrust balance, which is induced by the steady-state plasma production, is measured by a high resolution laser sensor.…”

Section: B Thrust Balance Calibration For Steady-state Forcementioning

confidence: 99%

Measurement of plasma momentum exerted on target by a small helicon plasma thruster and comparison with direct thrust measurement

Takahashi

Komuro

Andõ

2015

Review of Scientific Instruments

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“…The electron temperature is increased up to a few tens of eV [18], and the electrons ionize the propellant gas by inelastic collisions. The energetic electrons are expelled at the open side of the cavity (exhaust) by two main processes: plasma expansion (driven by the electron pressure) and diamagnetic effects in the divergent magnetic field [25,[27][28][29][30][31]. The difference of mobility between the ions and the electrons creates an ambipolar electric field that maintains the quasi-neutrality of the current-free plasma beam and accelerates the ions.…”

Section: A Description Of the Thruster Technology And Prototypesmentioning

confidence: 99%

Direct Thrust Measurement of an Electron Cyclotron Resonance Plasma Thruster

Vialis

Jarrige

Packan

et al. 2018

Journal of Propulsion and Power

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“…The force exerted by the plasma can be obtained from the difference in the signal between 'RF on' and 'RF off' as analyzed in Ref. [25]. It should be mentioned that the positive change in V r and V z correspond to the forces in the radially outward and axially downward directions.…”

Section: Simultaneous Measurements Of Local Axial and Radial Momentummentioning

confidence: 99%

Simultaneous Measurements of Local Axial and Radial Momentum Fluxes near a Radial Wall of a Helicon Source

Sugawara

Takahashi

Andõ

2019

Plasma and Fusion Research

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Axial and radial momentum fluxes near a lateral wall in a helicon plasma source are preliminarily investigated by installing a momentum vector measurement instrument, which has a detector plate mounted on a double-pendulum structure movable in both the axial and radial directions. The result demonstrates the presence of the axial momentum flux transferred to the radial wall, which seems to be delivered by the ions having the axial velocity and lost to the wall. Furthermore, a significantly greater radial momentum flux is lost to the radial wall, implying that the energy loss occurs at the radial wall. The presently shown technique would be useful for identifying the spatial profile of the momentum vector of the plasma.The momentum flux of plasmas is one of the crucial physical quantities associated with acceleration, transport, and confinement of various plasmas [1][2][3][4], since many of the plasma characteristics are well described by momentum equations, which imply that the external forces applied to fluids are balanced to their momentum flux. Therefore, the momentum balance is very often used to model various plasmas ranging from naturally occurring plasmas to artificially-made terrestrial plasmas in small laboratories.One of the direct applications of the plasma momentum flux is an electric propulsion for spacecrafts [5]. The performance of the propulsion devices can be typically characterized by a thrust-to-power ratio F/P, a specific impulse I sp , and a thruster efficiency η p , where F and P are the thrust and the electric power, respectively [6]. The latter two are defined aswhere m dot and g are the mass flow rate of the propellant and the gravitational acceleration at sea level, respectively. Since all of the assessment parameters are given by the thrust F and the well-controlled parameters such as the electric power P and the mass flow rate m dot , the measurement of the thrust F should be taken on top priority to assess the thruster performance in laboratories. According to a momentum conservation of the spacecraft and the exhausted propellant, the thrust force is equal in magnitude and opposite in direction to the momentum flux exhausted from the spacecraft as well known as a rocket equation [6]. Therefore, the direct measurement of the thrust is indeed equivalent to the identification of the absolute value of the total momentum flux of the plasma; being also useful for understanding other plasmas if the local momentum flux can be identified.The direct and individual measurements of the total thrust and thrust components exerted to the axial wall, the radial wall, and the magnetic nozzle have clarified many aspects of physics in a magnetic nozzle helicon plasma thruster [7][8][9][10][11][12][13][14][15]. In highly ionized conditions, e.g., for propellants of xenon and krypton, or for several kW rf power in argon, the axially negative force on the radial wall, which directs to the downstream side and is integrated over the whole inner surface, has been detected in the individual measurement of the ...

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Effect of magnetic and physical nozzles on plasma thruster performance

Cited by 47 publications

References 38 publications

Measurement of plasma momentum exerted on target by a small helicon plasma thruster and comparison with direct thrust measurement

Measurement of plasma momentum exerted on target by a small helicon plasma thruster and comparison with direct thrust measurement

Direct Thrust Measurement of an Electron Cyclotron Resonance Plasma Thruster

Simultaneous Measurements of Local Axial and Radial Momentum Fluxes near a Radial Wall of a Helicon Source

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