Comparison of Helical and Helicon Antennas as Sources of Plasma Excitation Using a Full Wave 3D Electromagnetic Analysis in Vacuum

Stratakos, Yorgos; Zeniou, Angelos; Gogolides, Εvangelos

doi:10.1002/ppap.201600107

Cited by 7 publications

(5 citation statements)

References 27 publications

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“…In helicon plasma systems, the coil is coupled to the RF generator through the helical spring-like structure, and a propagating wave (W-mode) helicon plasma is obtained by the effect of the magnetic field (100–300 G) [ 35 ]. A theoretical study to optimize the various antennas as a potential plasma source to produce IC plasma by Gogolides et al stated that, the electric field was scale with the number of loops of the coil for a constant current [ 37 ]. Compared to the ICP systems, a CCP system consists of two parallel plate electrodes, where the electrostatic waves (E-mode) are produced in between these two parallel plate electrodes, which are capacitively coupled to the RF source for the plasma discharge.…”

Section: Plasma: Potential Approach For Carbon Nanowall (Cnw) Syntmentioning

confidence: 99%

Oriented Carbon Nanostructures by Plasma Processing: Recent Advances and Future Challenges

et al. 2018

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Carbon, one of the most abundant materials, is very attractive for many applications because it exists in a variety of forms based on dimensions, such as zero-dimensional (0D), one-dimensional (1D), two-dimensional (2D), and-three dimensional (3D). Carbon nanowall (CNW) is a vertically-oriented 2D form of a graphene-like structure with open boundaries, sharp edges, nonstacking morphology, large interlayer spacing, and a huge surface area. Plasma-enhanced chemical vapor deposition (PECVD) is widely used for the large-scale synthesis and functionalization of carbon nanowalls (CNWs) with different types of plasma activation. Plasma-enhanced techniques open up possibilities to improve the structure and morphology of CNWs by controlling the plasma discharge parameters. Plasma-assisted surface treatment on CNWs improves their stability against structural degradation and surface chemistry with enhanced electrical and chemical properties. These advantages broaden the applications of CNWs in electrochemical energy storage devices, catalysis, and electronic devices and sensing devices to extremely thin black body coatings. However, the controlled growth of CNWs for specific applications remains a challenge. In these aspects, this review discusses the growth of CNWs using different plasma activation, the influence of various plasma-discharge parameters, and plasma-assisted surface treatment techniques for tailoring the properties of CNWs. The challenges and possibilities of CNW-related research are also discussed.

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Section: Plasma: Potential Approach For Carbon Nanowall (Cnw) Syntmentioning

confidence: 99%

Oriented Carbon Nanostructures by Plasma Processing: Recent Advances and Future Challenges

et al. 2018

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“…In addition, the effects of Faraday shield also been verified in some other experiments, a review and summary of works can be found in Refs. [24, 25].…”

Section: Resultsmentioning

confidence: 99%

“…Later, Boswell and Chen [ 23 ] studied the influence of the use of Faraday shield on plasma density. In the research studies of Stratakos, [ 24,25 ] detailed simulations of the Faraday shielding of a half‐Nagoya antenna and a Nagoya III antenna were carried out using the CST simulation software.…”

Section: Introductionmentioning

confidence: 99%

Simulation of the electromagnetic characters of a Faraday‐shielded antenna in a helicon wave plasma source

Zhou

Tan

et al. 2021

Contributions to Plasma Physics

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In this article, a structure that employs a Faraday shield between the Shoji antenna and the dielectric tube, which aims to reduce the dielectric wall sputtering, is investigated for the helicon wave plasma (HWP) sources. Faraday shield is usually used between the antenna and the reaction chamber to reduce the radiation from the high electromagnetic field generation, as well as to prevent the sputtering of the antenna material from polluting the reaction chamber during the discharge. Here, the influence of the Faraday shield on the longitudinal and radial electric field of the antenna is analysed through COMSOL MultiphysicsTM. Significant attenuations of both the longitudinal and radial fields are observed in the presence of the shield. In addition, by comparing the electric field distribution under two different shielding parameters, it is found that the shielding effects are not the same. Therefore, a detailed study of two kinds of design (pitch and gap) for the shield was carried out. The results show that the pitch has a little impact on the overall shielding effect when the gap is unaltered. The best shielding performance appears when we set the pitch at T of 8 and 10. In addition, the shielding effect also becomes worse as the gap increases while the pitch remains unchanged. A relatively good shielding effect can be produced by setting the gap to the value of 4–8 mm (a gap/pitch ratio of 2/15–4/15). This work provides a theoretical basis for designing a Faraday shield structure between the antenna and the dielectric tube, which is helpful to realize stable and controllable HWP discharges.

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“…From the real and imaginary parts of the impedance, it was concluded that the single-loop out-performs the other two at low densities, and that the type-III Nagoya behaves better at higher magnetic fields. Stratakos et al [33] used a commercially available fullwave 3-D electromagnetic analysis code (the CST microwave studio) to compare different antenna geometries. Four designs were discussed, that are, the two helical with N = 1 and 4, the half, and the full Nagoya type-III antennas.…”

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confidence: 99%

New Antenna Designs to Boost the Plasma Density in Helicon Sources

Ali

Antar

Costantine

2022

IEEE Trans. Plasma Sci.

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Plasma can be generated using radio frequency (RF) electromagnetic waves for a large variety of applications, such as energy and propulsion generation. Often, the desire is to achieve higher densities for given input power and helicon sources have demonstrated a high efficiency. The design of the antenna that couples the wave plays a major role in the efficiency of generating the plasma particles. Many geometries were studied and compared, but the relationship between the antenna characteristics and the plasma production is still missing. In this article, we identify the power-law dependence between the plasma density and the Gain of an antenna. The latter is determined using numerical simulations in a vacuum, whereas the former is acquired experimentally. The power-law dependence is obtained using four different antenna elements operating under the same experimental conditions on the Polaris linear plasma device. The design a posteriori of a new inductive antenna with a modified quadrifilar helix topology, exhibits not only a higher gain but also confirms the power law. The confirmation of this law will significantly impact the future of many technologies that leverage helicon plasmas.Index Terms-Antenna design, antenna gain, helicon plasma, magnetized plasma devices, radio frequency (RF) antenna. I. INTRODUCTIONP LASMA generation in laboratories has a wide range of applications in a variety of fields like in nuclear fusion [1], space thrusters [2], and plasma processing [3]. A large number of studies are thus dedicated to the production of hot and dense plasma using electromagnetic waves. In 1997, a first review, done by Chen and Boswell [4] presented an account of the understanding of helicon waves and the experimental results. Later in 2015, Chen [5] gave another comprehensive summary of the physics of helicon discharges. In 2018, Shinohara [6] wrote an overview of the experimental results related to radio frequency (RF) sources and their applications.The first helicon plasma source was achieved in an experiment conducted by Lehane and Thoneman [7]. Later on,

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Comparison of Helical and Helicon Antennas as Sources of Plasma Excitation Using a Full Wave 3D Electromagnetic Analysis in Vacuum

Cited by 7 publications

References 27 publications

Oriented Carbon Nanostructures by Plasma Processing: Recent Advances and Future Challenges

Oriented Carbon Nanostructures by Plasma Processing: Recent Advances and Future Challenges

Simulation of the electromagnetic characters of a Faraday‐shielded antenna in a helicon wave plasma source

New Antenna Designs to Boost the Plasma Density in Helicon Sources

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