An Experimental Investigation of Cathode Spot Motion in a Magnetically Rotating Arc Plasma Generator at Atmospheric Pressure

Wang, Cheng; Li, Jianqiao; Zhang, Zelong; Ye, Lei; Xia, Weiluo; Xia, Weidong

doi:10.1007/s11090-018-9937-8

Cited by 14 publications

(12 citation statements)

References 41 publications

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“…Thus, the deposition pressure is approximately 1 atm. A more detailed description of the experimental apparatus can be found in the authors' previous work [31,[44][45][46].…”

Section: Experimental Apparatusmentioning

confidence: 99%

Effects of Buffer Gases on Graphene Flakes Synthesis in Thermal Plasma Process at Atmospheric Pressure

et al. 2020

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A thermal plasma process at atmospheric pressure is an attractive method for continuous synthesis of graphene flakes. In this paper, a magnetically rotating arc plasma system is employed to investigate the effects of buffer gases on graphene flakes synthesis in a thermal plasma process. Carbon nanomaterials are prepared in Ar, He, Ar-H2, and Ar-N2 via propane decomposition, and the product characterization is performed by transmission electron microscopy (TEM), Raman spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and the Brunauer–Emmett–Teller (BET) method. Results show that spherical particles, semi-graphitic particles, and graphene flakes coexist in products under an Ar atmosphere. Under an He atmosphere, all products are graphene flakes. Graphene flakes with fewer layers, higher crystallinity, and a larger BET surface area are prepared in Ar-H2 and Ar-N2. Preliminary analysis reveals that a high-energy environment and abundant H atoms can suppress the formation of curved or closed structures, which leads to the production of graphene flakes with high crystallinity. Furthermore, nitrogen-doped graphene flakes with 1–4 layers are successfully synthesized with the addition of N2, which indicates the thermal plasma process also has great potential for the synthesis of nitrogen-doped graphene flakes due to its continuous manner, cheap raw materials, and adjustable nitrogen-doped content.

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“…Thus, the deposition pressure is approximately 1 atm. A more detailed description of the experimental apparatus can be found in the authors' previous work [31,[44][45][46].…”

Section: Experimental Apparatusmentioning

confidence: 99%

Effects of Buffer Gases on Graphene Flakes Synthesis in Thermal Plasma Process at Atmospheric Pressure

et al. 2020

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“…As the gas flow rate increases to 25 slm, the diameter of the arc column decreases because the cooling effect of the inlet gas is enhanced, and the number of multiple arc roots decreases from 3 to 2 simultaneously, as shown in Figure . According to previous results, this phenomenon is mainly associated with the thickness of the cold gas boundary layer between the anode nozzle wall and the arc column. The arc column still maintains a stable state, and therefore the plasma jet can be operated in the laminar flow in this case.…”

Section: Resultsmentioning

confidence: 59%

“…At 22.5 slm flow rate, three stationary, luminous anode spots appear on the anode just inside the nozzle entrance. It can be seen that the arc column is always connected to these spots simultaneously, and therefore multiple anode arc roots have formed . The arc roots are quite stable, and hence the arc column can sustain a rather steady shape with minor voltage fluctuation, as shown in Figure .…”

Section: Resultsmentioning

confidence: 93%

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Production of long, laminar plasma jets at atmospheric pressure with multiple cathodes

Wang

Cui

Zhang

et al. 2017

Contributions to Plasma Physics

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Plasma jets from conventional non-transferred arc plasma devices are usually operated in turbulent flows at atmospheric pressure. In this paper, a novel non-transferred arc plasma device with multiple cathodes is introduced to produce long, laminar plasma jets at atmospheric pressure. A pure helium atmosphere is used to produce a laminar plasma jet with a maximum length of >60 cm. The influence of gas components, arc currents, anode nozzle diameter, and gas flow rate on the jet characteristics is experimentally studied. The results reveal that the length of the plasma jet increases with increasing helium content and arc current but decreases with increasing nozzle diameter. As the gas flow rate increases, the length of the plasma jet initially increases and then decreases. Accordingly, the plasma jet is transformed from a laminar state to a transitional state and finally to a turbulent state. Furthermore, the anode arc root behaviours corresponding to different plasma jet flows are studied. In conclusion, the multiple stationary arc roots that exist on the anode just inside the nozzle entrance are favourable for the generation of a laminar plasma jet in this device. KEYWORDSanode arc root, arc plasma, jet length, laminar plasma jet, multiple cathodes 1.

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“…al. [30] investigated the variation of cathode spot rotation velocity, erosion rate, and qualitative spot diameter under the in uence of the magnetic eld, gas ow rate, and arc current. While most works were conducted for arc sources in vacuum conditions, the research lacked experimental camera data for medium pressure regimes (for air plasma).…”

Section: Iccd High-speed Camera Experimentsmentioning

confidence: 99%

Characterization of a Circular Arc Electron Source for a Self-Neutralizing Air-Breathing Plasma Thruster

Taploo,

Soni,

Solomon

et al. 2023

Preprint

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The paper presents an enhanced version of a circular arc electron source designed for air ionization applications in a self-neutralizing air-breathing plasma thruster. The arc electron source is specifically suited for the air-breathing plasma thruster, as it allows precise control of electron energy levels. This paper focuses on the ionization aspects of air-breathing thrusters through the development of a radially magnetized arc electron source. This source consists of a circular configuration of a metallic arc plasma source coupled with a positively biased grid to extract electrons and control electron energy. The average energy of electrons in the circular arc electron source is regulated by adjusting the bias voltage of the grid within the range of 0 V – 300 V. To investigate the behavior of ion current density and electron density concerning pressure and electron energy, the current probe and magnetic filter were utilized. It was demonstrated that the radial electron source leads to enhanced ionization of airflow by achieving plasma densities greater than 1018 m− 3. By utilizing a high-speed camera, the arc spot was seen to move azimuthally due to the magnetic field. Furthermore, scanning electron microscopy and a conductance measurement system were employed to examine the deposition and conductance of the electron extraction grid. While the grid underwent deposition of about 600 microns, the conductance was observed to increase/saturate with time and bias voltage, indicating an electrically “self-healing material”.

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An Experimental Investigation of Cathode Spot Motion in a Magnetically Rotating Arc Plasma Generator at Atmospheric Pressure

Cited by 14 publications

References 41 publications

Effects of Buffer Gases on Graphene Flakes Synthesis in Thermal Plasma Process at Atmospheric Pressure

Effects of Buffer Gases on Graphene Flakes Synthesis in Thermal Plasma Process at Atmospheric Pressure

Production of long, laminar plasma jets at atmospheric pressure with multiple cathodes

Characterization of a Circular Arc Electron Source for a Self-Neutralizing Air-Breathing Plasma Thruster

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