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You-nian Wang - One of the best experts on this subject based on the ideXlab platform.
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observation of nonlinear standing waves excited by plasma Series Resonance enhanced harmonics in capacitive discharges
Physical Review Letters, 2019Co-Authors: De-qi Wen, Michael A. Lieberman, Kai Zhao, Yongxin Liu, Demetre J Economou, You-nian WangAbstract:We report the first experimental observation of nonlinear standing waves excited by plasma-Series-Resonance-enhanced harmonics in low pressure, very high frequency, parallel plate, capacitively coupled plasmas. Spatial structures of the harmonics of the magnetic field, measured by a magnetic probe, are in very good agreement with simulations based on a nonlinear electromagnetics model. At relatively low pressure, the nonlinear sheath motion generates high-order harmonics that can be strongly enhanced near the Series Resonance frequencies. Satisfying certain conditions, such nonlinear harmonics induce radial standing waves, with voltage and current maxima on axis, resulting in center-high plasma density. Excitation of higher harmonics is suppressed at higher pressures.
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Nonlinear Series Resonance and standing waves in dual-frequency capacitive discharges
Plasma Sources Science and Technology, 2016Co-Authors: De-qi Wen, Emi Kawamura, Michael A. Lieberman, A J Lichtenberg, You-nian WangAbstract:It is well-known that the nonlinear Series Resonance in a high frequency capacitive discharge enhances the electron power deposition and also creates standing waves which produce radially center-high rf voltage profiles. In this work, the dynamics of Series Resonance and wave effects are examined in a dual-frequency driven discharge, using an asymmetric radial transmission line model incorporating a Child law sheath. We consider a cylindrical argon discharge with a conducting electrode radius of 15 cm, gap length of 3 cm, with a base case having a 60 MHz high frequency voltage of 250 V and a 10 MHz low frequency voltage of 1000 V, with a high frequency phase shift between the two frequencies. For this phase shift there is only one sheath collapse, and the time-averaged spectral peaks of the normalized current density at the center are mainly centered on harmonic numbers 30 and 50 of the low frequency, corresponding to the first standing wave Resonance frequency and the Series Resonance frequency, respectively. The effects of the waves on the Series Resonance dynamics near the discharge center give rise to significant enhancements in the electron power deposition, compared to that near the discharge edge. Adjusting the phase shift from π to 0, or decreasing the low frequency from 10 to 2 MHz, results in two or more sheath collapses, respectively, making the dynamics more complex. The sudden excitation of the perturbed Series Resonance current after the sheath collapse results in a current oscillation amplitude that is estimated from analytical and numerical calculations. Self-consistently determining the dc bias and including the conduction current is found to be important. The subsequent slow time variation of the high frequency oscillation is analyzed using an adiabatic theory.
Michael A. Lieberman - One of the best experts on this subject based on the ideXlab platform.
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observation of nonlinear standing waves excited by plasma Series Resonance enhanced harmonics in capacitive discharges
Physical Review Letters, 2019Co-Authors: De-qi Wen, Michael A. Lieberman, Kai Zhao, Yongxin Liu, Demetre J Economou, You-nian WangAbstract:We report the first experimental observation of nonlinear standing waves excited by plasma-Series-Resonance-enhanced harmonics in low pressure, very high frequency, parallel plate, capacitively coupled plasmas. Spatial structures of the harmonics of the magnetic field, measured by a magnetic probe, are in very good agreement with simulations based on a nonlinear electromagnetics model. At relatively low pressure, the nonlinear sheath motion generates high-order harmonics that can be strongly enhanced near the Series Resonance frequencies. Satisfying certain conditions, such nonlinear harmonics induce radial standing waves, with voltage and current maxima on axis, resulting in center-high plasma density. Excitation of higher harmonics is suppressed at higher pressures.
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Nonlinear Series Resonance and standing waves in dual-frequency capacitive discharges
Plasma Sources Science and Technology, 2016Co-Authors: De-qi Wen, Emi Kawamura, Michael A. Lieberman, A J Lichtenberg, You-nian WangAbstract:It is well-known that the nonlinear Series Resonance in a high frequency capacitive discharge enhances the electron power deposition and also creates standing waves which produce radially center-high rf voltage profiles. In this work, the dynamics of Series Resonance and wave effects are examined in a dual-frequency driven discharge, using an asymmetric radial transmission line model incorporating a Child law sheath. We consider a cylindrical argon discharge with a conducting electrode radius of 15 cm, gap length of 3 cm, with a base case having a 60 MHz high frequency voltage of 250 V and a 10 MHz low frequency voltage of 1000 V, with a high frequency phase shift between the two frequencies. For this phase shift there is only one sheath collapse, and the time-averaged spectral peaks of the normalized current density at the center are mainly centered on harmonic numbers 30 and 50 of the low frequency, corresponding to the first standing wave Resonance frequency and the Series Resonance frequency, respectively. The effects of the waves on the Series Resonance dynamics near the discharge center give rise to significant enhancements in the electron power deposition, compared to that near the discharge edge. Adjusting the phase shift from π to 0, or decreasing the low frequency from 10 to 2 MHz, results in two or more sheath collapses, respectively, making the dynamics more complex. The sudden excitation of the perturbed Series Resonance current after the sheath collapse results in a current oscillation amplitude that is estimated from analytical and numerical calculations. Self-consistently determining the dc bias and including the conduction current is found to be important. The subsequent slow time variation of the high frequency oscillation is analyzed using an adiabatic theory.
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nonlinear standing wave excitation by Series Resonance enhanced harmonics in low pressure capacitive discharges
Plasma Sources Science and Technology, 2015Co-Authors: Michael A. Lieberman, Emi Kawamura, A J Lichtenberg, A M MarakhtanovAbstract:It is well-known that standing waves having radially center-high rf voltage profiles exist in high frequency capacitive discharges. It is also known that in radially uniform discharges, the capacitive sheath nonlinearities excite strong nonlinear Series Resonance harmonics that enhance the electron power deposition. In this work, we consider the coupling of the Series Resonance-enhanced harmonics to the standing waves. A one-dimensional, asymmetric radial transmission line model is developed incorporating the wave and nonlinear sheath physics and a self-consistent dc potential, for both conducting and insulating electrode surfaces. The resulting coupled pde equation set is solved numerically to determine the discharge voltages and currents. A 10 mTorr argon plasma is chosen with density m−3, gap width 2 cm and conducting electrode radius 15 cm, driven by a 500 V rf source with resistance 0.5 . We examine a set of frequencies from near 30 MHz up to frequencies more than three times as high. For most frequencies, no harmonics correspond exactly with the Series or spatial Resonances, which is the generic situation. Nevertheless, nearby Resonances lead to a significantly enhanced ratio of the electron power per unit area on axis, compared to the average. Nearly similar results are found for insulating electrodes. Strong effects are seen for varying source resistance: high (50 ) resistance damps out most of the harmonic activity, while zero source resistance leads to a non-steady discharge with bias voltage relaxation oscillations. Stronger harmonic effects are seen for an increased radius of 30 cm, as lower harmonics become spatially resonant at lower frequencies. The radial dependence of electron power with frequency showed significant variations, with the central enhancement and sharpness of the spatial Resonances depending in a complicated way on the amplitudes of the nearby Series Resonance current harmonics and the phase relations among the voltage harmonics driving these current harmonics. Significant center/average electron power per unit area enhancement is found even at the lowest frequencies for both high and low densities: 4.5 at 30 MHz and m−3, and 2.2 at m−3.
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the effects of nonlinear Series Resonance on ohmic and stochastic heating in capacitive discharges
Physics of Plasmas, 2008Co-Authors: Michael A. Lieberman, Emi Kawamura, A J Lichtenberg, Thomas Mussenbrock, Ralf Peter BrinkmannAbstract:The flow of electron and ion conduction currents across a nonlinear capacitive sheath to the electrode surface self-consistently sets the dc bias voltage across the sheath. We incorporate these currents into a model of a homogeneous capacitive sheath in order to determine the enhancement of the Ohmic and stochastic heating due to self-excitation of the nonlinear Series Resonance in an asymmetric capacitive discharge. At lower pressures, the Series Resonance can enhance both the Ohmic and stochastic heating by factors of 2–4, with the Ohmic heating tending to zero as the pressure decreases. The model was checked, for a particular set of parameters, by a particle-in-cell (PIC) simulation using the homogeneous sheath approximation, giving good agreement. With a self-consistent Child-law sheath, the PIC simulation showed increased heating, as expected, whether the Series Resonance is important or not.
Hamid Radmanesh - One of the best experts on this subject based on the ideXlab platform.
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Bridge Type Series Resonance Transient Current Limiter for Medium-Voltage Smart Grids Application
2020Co-Authors: Hamid Radmanesh, Amir HeidaryAbstract:The main propose of this paper is to protect medium voltage smart grid applications from damages of the destructive fault current based on resonant type fault current limiter. Because of the Series connection of a capacitor and a reactor, the Series Resonance Fault Current Limiter (SRFCL) is invisible during normal operation and shows negligible impedance in the line. During the fault, a control circuit connects a rectifier bridge to the Series reactor and induces a DC voltage on it. In this instant, the Series reactor is short circuited, and the Series capacitor remains in the line. Thus, the impedance of the Series capacitor reduces the amplitude of the fault current.
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Distribution Network Protection Using Smart Dual Functional Series Resonance-Based Fault Current and FerroResonance Overvoltage Limiter
IEEE Transactions on Smart Grid, 2018Co-Authors: Hamid RadmaneshAbstract:This paper proposes a smart dual function Series Resonance ferroResonance overvoltage and fault current limiter (SRFFCL) for distribution networks. The studied network has potential transformers (PTs) with a typically low thermal capacity and high accuracy. The PT core losses are assumed to be constant during ferroResonance oscillation. The MATLAB software is used for simulation of the novel SRFFCL in distribution network, to study the PT ferroResonance overvoltage and fault current. Also, experimental results are obtained using a laboratory prototype. Both the simulation and experimental results, which are in good agreement with each other, show that the suggested SRFFCL can not only control the fault current but also adequately decrease the ferroResonance oscillation of the PT.
De-qi Wen - One of the best experts on this subject based on the ideXlab platform.
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observation of nonlinear standing waves excited by plasma Series Resonance enhanced harmonics in capacitive discharges
Physical Review Letters, 2019Co-Authors: De-qi Wen, Michael A. Lieberman, Kai Zhao, Yongxin Liu, Demetre J Economou, You-nian WangAbstract:We report the first experimental observation of nonlinear standing waves excited by plasma-Series-Resonance-enhanced harmonics in low pressure, very high frequency, parallel plate, capacitively coupled plasmas. Spatial structures of the harmonics of the magnetic field, measured by a magnetic probe, are in very good agreement with simulations based on a nonlinear electromagnetics model. At relatively low pressure, the nonlinear sheath motion generates high-order harmonics that can be strongly enhanced near the Series Resonance frequencies. Satisfying certain conditions, such nonlinear harmonics induce radial standing waves, with voltage and current maxima on axis, resulting in center-high plasma density. Excitation of higher harmonics is suppressed at higher pressures.
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Nonlinear Series Resonance and standing waves in dual-frequency capacitive discharges
Plasma Sources Science and Technology, 2016Co-Authors: De-qi Wen, Emi Kawamura, Michael A. Lieberman, A J Lichtenberg, You-nian WangAbstract:It is well-known that the nonlinear Series Resonance in a high frequency capacitive discharge enhances the electron power deposition and also creates standing waves which produce radially center-high rf voltage profiles. In this work, the dynamics of Series Resonance and wave effects are examined in a dual-frequency driven discharge, using an asymmetric radial transmission line model incorporating a Child law sheath. We consider a cylindrical argon discharge with a conducting electrode radius of 15 cm, gap length of 3 cm, with a base case having a 60 MHz high frequency voltage of 250 V and a 10 MHz low frequency voltage of 1000 V, with a high frequency phase shift between the two frequencies. For this phase shift there is only one sheath collapse, and the time-averaged spectral peaks of the normalized current density at the center are mainly centered on harmonic numbers 30 and 50 of the low frequency, corresponding to the first standing wave Resonance frequency and the Series Resonance frequency, respectively. The effects of the waves on the Series Resonance dynamics near the discharge center give rise to significant enhancements in the electron power deposition, compared to that near the discharge edge. Adjusting the phase shift from π to 0, or decreasing the low frequency from 10 to 2 MHz, results in two or more sheath collapses, respectively, making the dynamics more complex. The sudden excitation of the perturbed Series Resonance current after the sheath collapse results in a current oscillation amplitude that is estimated from analytical and numerical calculations. Self-consistently determining the dc bias and including the conduction current is found to be important. The subsequent slow time variation of the high frequency oscillation is analyzed using an adiabatic theory.
A J Lichtenberg - One of the best experts on this subject based on the ideXlab platform.
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Nonlinear Series Resonance and standing waves in dual-frequency capacitive discharges
Plasma Sources Science and Technology, 2016Co-Authors: De-qi Wen, Emi Kawamura, Michael A. Lieberman, A J Lichtenberg, You-nian WangAbstract:It is well-known that the nonlinear Series Resonance in a high frequency capacitive discharge enhances the electron power deposition and also creates standing waves which produce radially center-high rf voltage profiles. In this work, the dynamics of Series Resonance and wave effects are examined in a dual-frequency driven discharge, using an asymmetric radial transmission line model incorporating a Child law sheath. We consider a cylindrical argon discharge with a conducting electrode radius of 15 cm, gap length of 3 cm, with a base case having a 60 MHz high frequency voltage of 250 V and a 10 MHz low frequency voltage of 1000 V, with a high frequency phase shift between the two frequencies. For this phase shift there is only one sheath collapse, and the time-averaged spectral peaks of the normalized current density at the center are mainly centered on harmonic numbers 30 and 50 of the low frequency, corresponding to the first standing wave Resonance frequency and the Series Resonance frequency, respectively. The effects of the waves on the Series Resonance dynamics near the discharge center give rise to significant enhancements in the electron power deposition, compared to that near the discharge edge. Adjusting the phase shift from π to 0, or decreasing the low frequency from 10 to 2 MHz, results in two or more sheath collapses, respectively, making the dynamics more complex. The sudden excitation of the perturbed Series Resonance current after the sheath collapse results in a current oscillation amplitude that is estimated from analytical and numerical calculations. Self-consistently determining the dc bias and including the conduction current is found to be important. The subsequent slow time variation of the high frequency oscillation is analyzed using an adiabatic theory.
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nonlinear standing wave excitation by Series Resonance enhanced harmonics in low pressure capacitive discharges
Plasma Sources Science and Technology, 2015Co-Authors: Michael A. Lieberman, Emi Kawamura, A J Lichtenberg, A M MarakhtanovAbstract:It is well-known that standing waves having radially center-high rf voltage profiles exist in high frequency capacitive discharges. It is also known that in radially uniform discharges, the capacitive sheath nonlinearities excite strong nonlinear Series Resonance harmonics that enhance the electron power deposition. In this work, we consider the coupling of the Series Resonance-enhanced harmonics to the standing waves. A one-dimensional, asymmetric radial transmission line model is developed incorporating the wave and nonlinear sheath physics and a self-consistent dc potential, for both conducting and insulating electrode surfaces. The resulting coupled pde equation set is solved numerically to determine the discharge voltages and currents. A 10 mTorr argon plasma is chosen with density m−3, gap width 2 cm and conducting electrode radius 15 cm, driven by a 500 V rf source with resistance 0.5 . We examine a set of frequencies from near 30 MHz up to frequencies more than three times as high. For most frequencies, no harmonics correspond exactly with the Series or spatial Resonances, which is the generic situation. Nevertheless, nearby Resonances lead to a significantly enhanced ratio of the electron power per unit area on axis, compared to the average. Nearly similar results are found for insulating electrodes. Strong effects are seen for varying source resistance: high (50 ) resistance damps out most of the harmonic activity, while zero source resistance leads to a non-steady discharge with bias voltage relaxation oscillations. Stronger harmonic effects are seen for an increased radius of 30 cm, as lower harmonics become spatially resonant at lower frequencies. The radial dependence of electron power with frequency showed significant variations, with the central enhancement and sharpness of the spatial Resonances depending in a complicated way on the amplitudes of the nearby Series Resonance current harmonics and the phase relations among the voltage harmonics driving these current harmonics. Significant center/average electron power per unit area enhancement is found even at the lowest frequencies for both high and low densities: 4.5 at 30 MHz and m−3, and 2.2 at m−3.
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the effects of nonlinear Series Resonance on ohmic and stochastic heating in capacitive discharges
Physics of Plasmas, 2008Co-Authors: Michael A. Lieberman, Emi Kawamura, A J Lichtenberg, Thomas Mussenbrock, Ralf Peter BrinkmannAbstract:The flow of electron and ion conduction currents across a nonlinear capacitive sheath to the electrode surface self-consistently sets the dc bias voltage across the sheath. We incorporate these currents into a model of a homogeneous capacitive sheath in order to determine the enhancement of the Ohmic and stochastic heating due to self-excitation of the nonlinear Series Resonance in an asymmetric capacitive discharge. At lower pressures, the Series Resonance can enhance both the Ohmic and stochastic heating by factors of 2–4, with the Ohmic heating tending to zero as the pressure decreases. The model was checked, for a particular set of parameters, by a particle-in-cell (PIC) simulation using the homogeneous sheath approximation, giving good agreement. With a self-consistent Child-law sheath, the PIC simulation showed increased heating, as expected, whether the Series Resonance is important or not.
