Inductively coupled plasmas at low driving frequencies

Kolobov, Vladimir; Godyak, Valery

doi:10.1088/1361-6595/aa7584

Cited by 23 publications

(22 citation statements)

References 31 publications

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“…However, the magnetic RF field in RF ion sources is typically rather large 𝒪 (100G) because of the large applied powers and the rather low frequencies, which lead to a magnetization of the electrons and to nonlinear effects, such as the ponderomotive force. 23 This has to be accounted for in a selfconsistent description of the plasma heating mechanism in RF ion sources (see Sec. II E).…”

Section: B Icp Working Principle and Rf Plasma Heating Mechanismsmentioning

confidence: 99%

“…Because of the large magnetic RF field in this regime, it is important to retain the nonlinear RF Lorentz force in the electron momentum transport equation. 23,30,32 Theoretical modeling [36][37][38][39] and experimental measurements of the plasma density 13 indicate that the RF Lorentz force compresses the plasma via the ponderomotive effect. However, when the RF Lorentz force is accounted for in the electron momentum transport equation, the compression effect is largely overestimated, wherefore no numerical steady state solution was found.…”

Section: E Modeling Rf Coupling: Power Transfer To the Plasmamentioning

confidence: 99%

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Diagnostics of RF coupling in H− ion sources as a tool for optimizing source design and operational parameters

Briefi

Zielke

Rauner

et al. 2022

Review of Scientific Instruments

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Radio frequency (RF) driven H− ion sources are operated at very high power levels of up 100 kW in order to achieve the desired performance. For the experimental setup, these are demanding conditions possibly limiting the source reliability. Therefore, assessing the optimization potential in terms of RF power losses and the RF power transfer efficiency η to the plasma has moved to the focus of both experimental and numerical modeling investigations at particle accelerator and neutral beam heating sources for fusion plasmas. It has been demonstrated that, e.g., at typical neutral beam injection ion source setups, about half of the RF power provided by the generator is lost in the RF coil and the Faraday shield due to Joule heating or via eddy currents. In a best practice approach, it is exemplarily demonstrated at the ITER RF prototype ion source how experimental evaluation accompanied by numerical modeling of the ion source can be used to improve η. Individual optimization measures regarding the Faraday shield, the RF coil, the discharge geometry, the RF driving frequency, and the application of ferrites are discussed, which could reduce the losses by a factor of two. The provided examples are intended as exemplary guidelines, which can be applied at other setups in order to achieve with low-risk effort an optimized ion source design in terms of reduced losses and hence increased reliability.

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Section: B Icp Working Principle and Rf Plasma Heating Mechanismsmentioning

confidence: 99%

Section: E Modeling Rf Coupling: Power Transfer To the Plasmamentioning

confidence: 99%

Diagnostics of RF coupling in H− ion sources as a tool for optimizing source design and operational parameters

Briefi

Zielke

Rauner

et al. 2022

Review of Scientific Instruments

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“…Optimizing the RF power coupling in inductively driven radio frequency (RF) ion sources is a worthwhile task, since it can lead to significant improvement of the RF power transfer efficiency [1][2][3][4][5][6]…”

Section: Introductionmentioning

confidence: 99%

Predictive fluid model for self-consistent description of inductive RF coupling in powerful negative hydrogen ion sources

Zielke

Briefi

Lishev

et al. 2022

J. Phys.: Conf. Ser.

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RF-driven negative hydrogen ion sources are typically operated at low frequencies around 1 MHz, gas pressures around or below 1 Pa and large power densities up to 10 Wcm-3. Owing to these conditions as well as the current discharge geometries and antenna layouts, the RF power coupling is far from optimized, i.e. only a fraction η of the power delivered by the generator is absorbed by the plasma. This considerably limits the performance and reliability of RF-driven ion sources. To study the bidirectional RF power coupling a self-consistent fluid model is introduced. Taking into account the interplay between the nonlinear RF Lorentz force and the electron viscosity (usually neglected in state-of-the-art fluid models) a steady state solution is obtained, where the trends reflect the experimental data. Solutions calculated in hydrogen but with increased ion masses indicate that the latter are responsible for the systematically increased η, which is observed experimentally when deuterium instead of hydrogen is used as feed gas.

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“…Cheng et al used the CFD-ACE+ software to study the sensitivity of structural parameters on the uniformity of plasma parameters based on a regression orthogonal design [14]. Kolovol et al discussed possible effects of RF magnetic field on ICP at different driving frequencies with simulation of plasma dynamics, including localized electromagnetic fields at most frequencies [15]. Commercial multiphysics software named COMSOL Multiphysics was employed here, with the consideration of multi-physics process including electromagnetic field and fluid dynamics.…”

Section: Introductionmentioning

confidence: 99%

Experimental and simulation investigation of electrical and plasma parameters in a low pressure inductively coupled argon plasma

Yang

et al. 2017

Plasma Sci. Technol.

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The electrical and plasma parameters of a low pressure inductively coupled argon plasma are investigated over a wide range of parameters (RF power, flow rate and pressure) by diverse characterizations. The external antenna voltage and current increase with the augment of RF power, whereas decline with the enhancement of gas pressure and flow rate conversely. Compared with gas flow rate and pressure, the power transfer efficiency is significantly improved by RF power, and achieved its maximum value of 0.85 after RF power injected excess 125 W. Optical emission spectroscopy (OES) provides the local mean values of electron excited temperature and electron density in inductively coupled plasma (ICP) post regime, which vary in a range of 0.81 eV to 1.15 eV and 3.7 10 m 16 3 to 8.7 10 m , 17 3 respectively. Numerical results of the average magnitudes of electron temperature and electron density in twodimensional distribution exhibit similar variation trend with the experimental results under different operating condition by using COMSOL Multiphysics. By comprehensively understanding the characteristics in a low pressure ICP, optimized operating conditions could be anticipated aiming at different academic and industrial applications.

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Inductively coupled plasmas at low driving frequencies

Cited by 23 publications

References 31 publications

Diagnostics of RF coupling in H− ion sources as a tool for optimizing source design and operational parameters

Diagnostics of RF coupling in H− ion sources as a tool for optimizing source design and operational parameters

Predictive fluid model for self-consistent description of inductive RF coupling in powerful negative hydrogen ion sources

Experimental and simulation investigation of electrical and plasma parameters in a low pressure inductively coupled argon plasma

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