scholarly journals Automatically Controlled Frequency-Tunable rf Plasma Thruster: Ion Beam and Thrust Measurements

2021 ◽  
Vol 9 ◽  
Author(s):  
Kazunori Takahashi ◽  
Ryoji Imai ◽  
Kengo Hanaoka
Keyword(s):  
Ion Beam ◽  
Impedance Matching ◽  
Rf Plasma ◽  
Rf Power ◽  
Ion Energy Distribution ◽  
Single Turn ◽  
Magnetic Nozzle ◽  
Plasma Thruster ◽  
Frequency Tunable ◽  
The Stability

A fast and automatically controlled frequency-tunable radiofrequency (rf) system is installed in an rf plasma thruster consisting of a stepped-diameter insulator source tube wound by a single-turn loop antenna and a solenoid providing a magnetic nozzle, and immersed in vacuum. The frequency and the output power are controlled so as to minimize the reflection coefficient and to maintain the net power corresponding to the forward minus reflected powers at a constant level. The reproducibility of the impedance matching and the stability of the net rf power are assessed, showing the fast impedance matching within about 10 msec and the long and stable delivery of the rf power to the thruster. When increasing the rf power up to 500 W, discontinuous changes in the source plasma density, the imparted thrust, and the signal intensity of the ion beam downstream of the thruster are observed, indicating effects of the discharge mode on the thruster performance and the ion energy distribution.

scholarly journals Magnetic nozzle radiofrequency plasma thruster approaching twenty percent thruster efficiency

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kazunori Takahashi
Keyword(s):  
Magnetic Field ◽  
Electric Propulsion ◽  
Transfer Efficiency ◽  
Rf Plasma ◽  
Power Transfer ◽  
Rf Power ◽  
Plasma Production ◽  
Magnetic Nozzle ◽  
Plasma Thruster ◽  
Power Transfer Efficiency

AbstractDevelopment of a magnetic nozzle radiofrequency (rf) plasma thruster has been one of challenging topics in space electric propulsion technologies. The thruster typically consists of an rf plasma source and a magnetic nozzle, where the plasma produced inside the source is transported along the magnetic field and expands in the magnetic nozzle. An imparted thrust is significantly affected by the rf power coupling for the plasma production, the plasma transport, the plasma loss to the wall, and the plasma acceleration process in the magnetic nozzle. The rf power transfer efficiency and the imparted thrust are assessed for two types of rf antennas exciting azimuthal mode number of $$m=+1$$ m = + 1 and $$m=0$$ m = 0 , where propellant argon gas is introduced from the upstream of the thruster source tube. The rf power transfer efficiency and the density measured at the radial center for the $$m=+1$$ m = + 1 mode antenna are higher than those for the $$m=0$$ m = 0 mode antenna, while a larger thrust is obtained for the $$m=0$$ m = 0 mode antenna. Two-dimensional plume characterization suggests that the lowered performance for the $$m=+1$$ m = + 1 mode case is due to the plasma production at the radial center, where contribution on a thrust exerted to the magnetic nozzle is weak due to the absence of the radial magnetic field. Subsequently, the configuration is modified so as to introduce the propellant gas near the thruster exit for the $$m=0$$ m = 0 mode configuration and the thruster efficiency approaching twenty percent is successfully obtained, being highest to date in the kW-class magnetic nozzle rf plasma thrusters.

scholarly journals Thrust imparted by a stepped-diameter magnetic nozzle rf plasma thruster

2018 ◽  
Vol 113 (3) ◽  
pp. 034101 ◽  
Author(s):  
Kazunori Takahashi ◽  
Yoshinori Takao ◽  
Akira Ando
Keyword(s):  
Rf Plasma ◽  
Magnetic Nozzle ◽  
Plasma Thruster

scholarly journals Experimental Characterization of the Capacitively Coupled RF-Plasma Thruster

2021 ◽  
Vol 11 (15) ◽  
pp. 6799
Author(s):  
Pavel Smirnov ◽  
Ruslan Kozakov ◽  
Jochen Schein
Keyword(s):  
Plasma Plume ◽  
Potential Drop ◽  
Rf Discharge ◽  
Rf Plasma ◽  
Capacitively Coupled ◽  
Plasma Generation ◽  
Magnetic Nozzle ◽  
Plasma Thruster ◽  
Nozzle Configuration ◽  
Emissive Probes

A novel design of a neutralizer-free plasma thruster is proposed. This setup features a capacitively coupled RF discharge for plasma generation combined with a magnetic nozzle configuration for acceleration. Characteristics of the plasma plume and ions flux are investigated with the help of emissive probes and retarding potential analyzers (RPA). Essential parameters of the thruster like ions energy, ions flux, utilization efficiencies, and thrust are estimated. The investigated system produces a beam of ions accelerated to an energy of 10 eV when operated at power levels of ~20 W and a mass flow of 1.2 mg/s. The ion energy coincides with the potential drop in the plasma plume indicating that the acceleration takes place due the formation of an ambipolar electric field in the expanding plasma. The design is compared to the data available of other similar thrusters.

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

2021 ◽  
Vol 55 (13) ◽  
pp. 135201
Author(s):  
Ryoji Imai ◽  
Kazunori Takahashi
Keyword(s):  
Lorentz Force ◽  
Momentum Flux ◽  
Ion Beam ◽  
Rf Plasma ◽  
Field Energy ◽  
Saturation Current ◽  
Current Profile ◽  
Plasma Thruster ◽  
Thrust Vector ◽  
Horizontal Thrust

Abstract 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.

scholarly journals Characterization and Performance of Carbon Films Deposited by Plasma and Ion Beam Based Techniques

1994 ◽  
Vol 354 ◽  
Author(s):  
K.C. Walter ◽  
H. Kung ◽  
T. Levine ◽  
J.T. Tesmer ◽  
P. Kodali ◽  
...  
Keyword(s):  
Wear Rate ◽  
Surface Area ◽  
Ion Beam ◽  
Carbon Films ◽  
The Self ◽  
Line Of Sight ◽  
Rf Power ◽  
Hard Carbon ◽  
Self Bias ◽  
Cathodic Arc

AbstractPlasma and ion beam based techniques have been used to deposit carbon-based films. The ion beam based method, a cathodic arc process, used a magnetically mass analyzed beam and is inherently a line-of-sight process. Two hydrocarbon plasma-based, non-line-of-sight techniques were also used and have the advantage of being capable of coating complicated geometries. The self-bias technique can produce hard carbon films, but is dependent on rf power and the surface area of the target. The pulsed-bias technique can also produce hard carbon films but has the additional advantage of being independent of rf power and target surface area. Tribological results indicated the coefficient of friction is nearly the same for carbon films from each deposition process, but the wear rate of the cathodic arc film was five times less than for the self-bias or pulsed-bias films. Although the cathodic arc film was the hardest, contained the highest fraction of sp3 bonds and exhibited the lowest wear rate, the cathodic arc film also produced the highest wear on the 440C stainless steel counterface during tribological testing. Thus, for tribological applications requiring low wear rates for both counterfaces, coating one surface with a very hard, wear resistant film may detrimentally affect the tribological behavior of the counterface.

Large Area Surface Treatment by Ion Beam Technology

1996 ◽  
Vol 438 ◽  
Author(s):  
R. L. C. Wu ◽  
W. Lanter
Keyword(s):  
Ion Beam ◽  
High Vacuum ◽  
Polycrystalline Diamond ◽  
Carbon Films ◽  
Ultra High Vacuum ◽  
Diamond Like Carbon ◽  
Chemical Compositions ◽  
Rf Power ◽  
Large Area ◽  
Ion Energy

AbstractAn ultra high vacuum ion beam system, consisting of a 20 cm diameter Rf excilted (13.56 MHz) ion gun and a four-axis substrate scanner, has been used to modify large surfaces (up to 1000 cm2) of various materials, including; infrared windows, silicon nitride, polycrystalline diamond, 304 and 316 stainless steels, 440C and M50 steels, aluminum alloys, and polycarbonates; by depositing different chemical compositions of diamond-like carbon films. The influences of ion energy, Rf power, gas composition (H2/CH4 , Ar/CH4 and O2/CH4/H2), on the diamond-like carbon characteristics has been studied. Particular attention was focused on adhesion, environmental effects, IR(3–12 μm) transmission, coefficient of friction, and wear factors under spacelike environments of diamond-like carbon films on various substrates. A quadrupole mass spectrometer was utilized to monitor the ion beam composition for quality control and process optimization.

Reduction of the Anode Fall in a Coaxial Plasma Thruster with an Applied Magnetic Nozzle

1994 ◽  
Author(s):  
Jay T. Scheuer ◽  
Robert P. Hoyt ◽  
Kurt F. Schoenberg ◽  
Richard A. Gerwin ◽  
Ronald W. Moses ◽  
...  
Keyword(s):  
Magnetic Nozzle ◽  
Plasma Thruster ◽  
Anode Fall
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