Modification of momentum flux lost to a radial wall of a helicon source by neutral injection

Takahashi, Kazunori; Sugawara, Takeharu; Andõ, Akira

doi:10.1063/5.0002173

Cited by 5 publications

(4 citation statements)

References 47 publications

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“…The IEDF can be obtained from the first derivative of the current-voltage characteristic of the collector electrode in the RFEA. Furthermore, the MVMI, which has been described previously [32][33][34] and shown in figure 3, is mounted on the stage to measure the two-dimensional profile of the horizontal Reprinted from [28], with the permission of AIP Publishing. momentum flux.…”

Section: Methodsmentioning

confidence: 99%

Deflections of dynamic momentum flux and electron diamagnetic thrust in a magnetically steered rf plasma thruster

Imai¹,

Takahashi²

2021

J. Phys. D: Appl. Phys.

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Two-dimensional characterization of the plasma plume is experimentally performed downstream of a magnetically steered radiofrequency plasma thruster, where the ion beam current, the ion saturation current, and the horizontal dynamic momentum flux, are measured by using the retarding field energy analyzer, the Langmuir probe, and the momentum vector measurement instrument, respectively, in addition to the previously measured horizontal thrust. The measurements show the deflections of the dynamic momentum flux including both the ions and the neutrals; the change in the direction of the dynamic momentum flux is consistent with the previously measured horizontal thrust. Furthermore, the ion saturation current profile implies that the deflected electron-diamagnetic-induced Lorentz force exerted to the magnetic nozzle contributes to the change in the thrust vector. Therefore, it is demonstrated that the deflections of both the dynamic momentum flux and the electron-diamagnetic-induced Lorentz force play an important role in the thrust vector control by the magnetic steering.

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Section: Methodsmentioning

confidence: 99%

Deflections of dynamic momentum flux and electron diamagnetic thrust in a magnetically steered rf plasma thruster

Imai¹,

Takahashi²

2021

J. Phys. D: Appl. Phys.

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“…This expectation is consistent with the previous observation that the momentum flux lost to the wall is enhanced when the axial density profile has a maximum in the upstream region of the source tube. [37][38][39] To discuss the impact of the normalized profile on the thrust component T B , the thrust normalized by I is integrated over the cross-section is plotted in Fig. 4(b), which is given by…”

Section: Resultsmentioning

confidence: 99%

Radial profile control of a magnetically expanding plasma and its impact on a plasma thruster

Sumikawa

Takahashi

2023

Jpn. J. Appl. Phys.

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Two radiofrequency (rf) loop antennas are wound around a source tube of an inductively coupled and magnetically expanding plasma. The magnetic field lines are convergent in the source and divergent downstream of the source tube. The rf antennas are independently powered by two rf generators, providing the change in the radial profile of the ion saturation current of a Langmuir probe. Peaks in the ion saturation currents are observed around the magnetic field lines intersecting the radial source wall at the rf antenna positions, implying the presence of the electrons created near the antennas and transported along the magnetic field lines. The results suggest that the radial profile of the magnetically expanding plasma can be controlled by superimposing the plasmas created by the two antennas. The impact of the radial profile on the thrust is preliminarily investigated by attaching only the solenoid to a pendulum thrust balance immersed in vacuum.

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“…The thruster consists of a 10.5 cm inner diameter and 26 cm long glass source tube wound by a double-turn rf loop antenna and a solenoid placed near the source exit, where the upstream side of the source tube (left-hand side of figure 1(a)) is terminated by an insulator mica plate. Argon gas is continuously introduced from the source exit via a 1 mm inner diameter and 2 mm outer diameter ceramic tube, by which the thruster performance has been improved in the previous experiment due to the modification of the neutral and plasma density profiles [34,35] and due to the inhibition of the momentum loss to the wall [36]. The argon gas flow rate is maintained at 70 sccm (2.1 mg s −1 ) by using a mass flow controller located outside of the chamber, where the gas pressure measured at the chamber sidewall is about 28 mPa and the effective pumping speed for argon is estimated as about 4500 L s −1 .…”

Section: Thruster Configurationmentioning

confidence: 99%

Experimental investigation on magnetic field strength providing thrust saturation in a magnetic nozzle radiofrequency plasma thruster

Takahashi,

Sumikawa

2023

Plasma Phys. Control. Fusion

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Magnetic field strength applied to a magnetic nozzle radiofrequency (rf) plasma thruster having a 10.5 cm diameter source tube is increased up to about 3 kG by pulsing the solenoid current. A target plate is installed at 30 cm downstream of the source and an impulse bit exerted to the target is measured to assess the thrust, where the thrust balance measurement was impossible due to the interaction between the pulsed magnetic fields and the eddy currents on surroundings. Since the diameter of the plasma plume at the target location is larger than the target diameter, a comparison between the thrust balance and target measurements under continuous magnetic field and rf power is performed prior to the pulsed magnetic field experiments, showing that about 65 percent of the plasma momentum is exerted to the target plate. Saturation of the impulse bit, being equivalent to the force multiplied by the rf pulse width, is clearly observed when increasing the magnetic field strength. The magnetic field providing the force saturation is found to be changed by the source diameter, which is qualitatively explained by considering a change in the plasma loss to the source wall in a thruster model containing the particle balance, power balance, and one-dimensional magnetic nozzle models. It is suggested that the magnetic field strength required for optimizing the force, i.e. the thrust, can be reduced when enlarging the source tube diameter.

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Modification of momentum flux lost to a radial wall of a helicon source by neutral injection

Cited by 5 publications

References 47 publications

Deflections of dynamic momentum flux and electron diamagnetic thrust in a magnetically steered rf plasma thruster

Deflections of dynamic momentum flux and electron diamagnetic thrust in a magnetically steered rf plasma thruster

Radial profile control of a magnetically expanding plasma and its impact on a plasma thruster

Experimental investigation on magnetic field strength providing thrust saturation in a magnetic nozzle radiofrequency plasma thruster

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