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Title: Radio-frequency wave interactions with a plasma sheath in oblique-angle magnetic fields using a sheath impedance model

Abstract

Here, the physics of interactions between waves in plasmas and sheaths for background magnetic fields which make oblique angles with the sheath surfaces is studied with the use of the self-consistent finite element code rfSOL incorporating the recently developed sheath impedance model. The calculation based on this model employs the generalized sheath boundary condition (sheath BC), which surpasses the previously used capacitive sheath BC in reliability by taking into account the contributions of the ion and electron currents in the sheath as well as the displacement current. A series of numerical simulations is carried out in two-dimensional slab geometry with a flat or curved sheath surface as part of the boundary. It is shown that the sheath–plasma wave appears when the equilibrium magnetic field line angle with respect to the sheath surface is small, the absolute value of the radio-frequency (RF) sheath voltage is large, and the plasma density is slightly higher than the lower hybrid resonance density (LHR density), all of which bring the sheath property closer to being capacitive. It is also shown that the sharp variation of the magnetic field line angle along the sheath surface can sensitively affect the maximum absolute value of the RF sheathmore » voltage at a plasma density slightly lower than the LHR density.« less

Authors:
ORCiD logo [1]; ORCiD logo [2]
  1. Kyushu Institute of Technology, Fukuoka (Japan)
  2. Lodestar Research Corp., Boulder, CO (United States)
Publication Date:
Research Org.:
Lodestar Research Corp., Boulder, CO (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Fusion Energy Sciences (FES)
OSTI Identifier:
1494126
Grant/Contract Number:  
FG02-97ER54392
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 26; Journal Issue: 2; Related Information: http://doi.org/10.5281/zenodo.1667247; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; radio-frequency; sheaths; fusion; finite-element method

Citation Formats

Kohno, H., and Myra, J. R. Radio-frequency wave interactions with a plasma sheath in oblique-angle magnetic fields using a sheath impedance model. United States: N. p., 2019. Web. doi:10.1063/1.5054920.
Kohno, H., & Myra, J. R. Radio-frequency wave interactions with a plasma sheath in oblique-angle magnetic fields using a sheath impedance model. United States. https://doi.org/10.1063/1.5054920
Kohno, H., and Myra, J. R. Fri . "Radio-frequency wave interactions with a plasma sheath in oblique-angle magnetic fields using a sheath impedance model". United States. https://doi.org/10.1063/1.5054920. https://www.osti.gov/servlets/purl/1494126.
@article{osti_1494126,
title = {Radio-frequency wave interactions with a plasma sheath in oblique-angle magnetic fields using a sheath impedance model},
author = {Kohno, H. and Myra, J. R.},
abstractNote = {Here, the physics of interactions between waves in plasmas and sheaths for background magnetic fields which make oblique angles with the sheath surfaces is studied with the use of the self-consistent finite element code rfSOL incorporating the recently developed sheath impedance model. The calculation based on this model employs the generalized sheath boundary condition (sheath BC), which surpasses the previously used capacitive sheath BC in reliability by taking into account the contributions of the ion and electron currents in the sheath as well as the displacement current. A series of numerical simulations is carried out in two-dimensional slab geometry with a flat or curved sheath surface as part of the boundary. It is shown that the sheath–plasma wave appears when the equilibrium magnetic field line angle with respect to the sheath surface is small, the absolute value of the radio-frequency (RF) sheath voltage is large, and the plasma density is slightly higher than the lower hybrid resonance density (LHR density), all of which bring the sheath property closer to being capacitive. It is also shown that the sharp variation of the magnetic field line angle along the sheath surface can sensitively affect the maximum absolute value of the RF sheath voltage at a plasma density slightly lower than the LHR density.},
doi = {10.1063/1.5054920},
url = {https://www.osti.gov/biblio/1494126}, journal = {Physics of Plasmas},
issn = {1070-664X},
number = 2,
volume = 26,
place = {United States},
year = {2019},
month = {2}
}

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Cited by: 3 works
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Works referenced in this record:

Far field sheaths from waves in the ion cyclotron range of frequencies
journal, September 1994


Numerical investigation of fast-wave propagation and radio-frequency sheath interaction with a shaped tokamak wall
journal, July 2015


Low‐power fast wave antenna loading as a radio‐frequency sheath diagnostic
journal, January 1996


Heat loads on JET plasma facing components from ICRF and LH wave absorption in the SOL
journal, August 2011


Helicon normal modes in Proto-MPEX
journal, May 2018


Nonlinear plasma sheath potential in the ASDEX Upgrade 3-strap antenna: a parameter scan
journal, August 2017


Radiofrequency sheaths and impurity generation by ICRF antennas
journal, April 1989


Studies of RF sheaths and diagnostics on IShTAR
conference, January 2015

  • Crombé, K.; Devaux, S.; D’Inca, R.
  • RADIO FREQUENCY POWER IN PLASMAS: Proceedings of the 21st Topical Conference, AIP Conference Proceedings
  • https://doi.org/10.1063/1.4936471

Radio frequency sheaths in an oblique magnetic field
journal, June 2015


Experimental Observation of Convective Cell Formation due to a Fast Wave Antenna in the Large Plasma Device
journal, November 2017


Modeling far-field radio-frequency sheaths in Alcator C-Mod
journal, May 2013


Characterization and performance of a field aligned ion cyclotron range of frequency antenna in Alcator C-Mod
journal, May 2013


Experimental study of sheath currents in the scrape-off layer during ICRH on TEXTOR
journal, April 1992


Nonlinear ICRF-plasma interactions
journal, June 2006


Benchmarking sheath subgrid boundary conditions for macroscopic-scale simulations
journal, December 2014


RF current distribution and topology of RF sheath potentials in front of ICRF antennae
journal, July 2005


Edge plasma density convection during ion cyclotron resonance heating on Tore Supra
journal, June 2002


Radio‐frequency‐sheath‐driven edge plasma convection and interaction with the H mode
journal, October 1993


Analytical solution for capacitive RF sheath
journal, January 1988


Full wave simulations of fast wave heating losses in the scrape-off layer of NSTX and NSTX-U
journal, May 2014


Power deposition in high‐density inductively coupled plasma tools for semiconductor processing
journal, June 1995


Radio-frequency sheaths physics: Experimental characterization on Tore Supra and related self-consistent modeling
journal, June 2014


Quantitative modeling of ICRF antennas with integrated time domain RF sheath and plasma physics
conference, January 2014

  • Smithe, David N.; D'Ippolito, Daniel A.; Myra, James R.
  • RADIOFREQUENCY POWER IN PLASMAS: Proceedings of the 20th Topical Conference, AIP Conference Proceedings
  • https://doi.org/10.1063/1.4864506

A finite element procedure for radio-frequency sheath–plasma interactions in the ion cyclotron range of frequencies
journal, October 2012


Slow-wave propagation and sheath interaction in the ion-cyclotron frequency range
journal, November 2009


The role of rectified currents in far-field RF sheaths and in SOL losses of HHFW power on NSTX
journal, August 2017


Spatial proximity effects on the excitation of sheath RF voltages by evanescent slow waves in the ion cyclotron range of frequencies
journal, January 2017


The interaction between waves in the ion cyclotron range of frequencies and the plasma boundary
journal, November 1993


Radio-frequency sheath-plasma interactions with magnetic field tangency points along the sheath surface
journal, August 2013


Numerical analysis of radio-frequency sheath-plasma interactions in the ion cyclotron range of frequencies
journal, January 2012


DC currents collected by a RF biased electrode quasi-parallel to the magnetic field
journal, January 2017


A post-processing method to simulate the generalized RF sheath boundary condition
journal, January 2017


Key results of long pulse ICRH operation in Tore Supra
journal, June 2006


Influence of boronization on the plasma performance in TEXTOR
journal, February 1989


First results with 3-strap ICRF antennas in ASDEX Upgrade
journal, July 2016


A radio-frequency sheath boundary condition and its effect on slow wave propagation
journal, October 2006


Connection coefficients for cold plasma wave propagation near metallic surfaces
journal, March 2013


Nonlinear ICRF-Plasma Interactions
conference, January 2005

  • Myra, J. R.
  • RADIO FREQUENCY POWER IN PLASMAS: 16th Topical Conference on Radio Frequency Power in Plasmas, AIP Conference Proceedings
  • https://doi.org/10.1063/1.2098187

    Works referencing / citing this record:

    A finite element procedure for radio-frequency sheath–plasma interactions in the ion cyclotron range of frequencies
    journal, October 2012


    The role of rectified currents in far-field RF sheaths and in SOL losses of HHFW power on NSTX
    journal, August 2017


    DC currents collected by a RF biased electrode quasi-parallel to the magnetic field
    journal, January 2017


    A post-processing method to simulate the generalized RF sheath boundary condition
    journal, January 2017


    Edge plasma density convection during ion cyclotron resonance heating on Tore Supra
    journal, June 2002


    A radio-frequency sheath boundary condition and its effect on slow wave propagation
    journal, October 2006


    Numerical analysis of radio-frequency sheath-plasma interactions in the ion cyclotron range of frequencies
    journal, January 2012


    Characterization and performance of a field aligned ion cyclotron range of frequency antenna in Alcator C-Mod
    journal, May 2013


    Radio-frequency sheath-plasma interactions with magnetic field tangency points along the sheath surface
    journal, August 2013


    Quantitative modeling of ICRF antennas with integrated time domain RF sheath and plasma physics
    conference, January 2014

    • Smithe, David N.; D'Ippolito, Daniel A.; Myra, James R.
    • RADIOFREQUENCY POWER IN PLASMAS: Proceedings of the 20th Topical Conference, AIP Conference Proceedings
    • https://doi.org/10.1063/1.4864506

    Radio-frequency sheaths physics: Experimental characterization on Tore Supra and related self-consistent modeling
    journal, June 2014


    Radio frequency sheaths in an oblique magnetic field
    journal, June 2015


    Numerical investigation of fast-wave propagation and radio-frequency sheath interaction with a shaped tokamak wall
    journal, July 2015


    Studies of RF sheaths and diagnostics on IShTAR
    conference, January 2015

    • Crombé, K.; Devaux, S.; D’Inca, R.
    • RADIO FREQUENCY POWER IN PLASMAS: Proceedings of the 21st Topical Conference, AIP Conference Proceedings
    • https://doi.org/10.1063/1.4936471

    Radio‐frequency‐sheath‐driven edge plasma convection and interaction with the H mode
    journal, October 1993


    Far field sheaths from waves in the ion cyclotron range of frequencies
    journal, September 1994


    Power deposition in high‐density inductively coupled plasma tools for semiconductor processing
    journal, June 1995


    Low‐power fast wave antenna loading as a radio‐frequency sheath diagnostic
    journal, January 1996


    Radiofrequency sheaths and impurity generation by ICRF antennas
    journal, April 1989


    RF current distribution and topology of RF sheath potentials in front of ICRF antennae
    journal, July 2005


    Nonlinear ICRF-plasma interactions
    journal, June 2006


    Key results of long pulse ICRH operation in Tore Supra
    journal, June 2006


    Heat loads on JET plasma facing components from ICRF and LH wave absorption in the SOL
    journal, August 2011


    Full wave simulations of fast wave heating losses in the scrape-off layer of NSTX and NSTX-U
    journal, May 2014


    First results with 3-strap ICRF antennas in ASDEX Upgrade
    journal, July 2016


    Influence of boronization on the plasma performance in TEXTOR
    journal, February 1989


    Experimental study of sheath currents in the scrape-off layer during ICRH on TEXTOR
    journal, April 1992


    The interaction between waves in the ion cyclotron range of frequencies and the plasma boundary
    journal, November 1993


    Slow-wave propagation and sheath interaction in the ion-cyclotron frequency range
    journal, November 2009


    Connection coefficients for cold plasma wave propagation near metallic surfaces
    journal, March 2013


    Modeling far-field radio-frequency sheaths in Alcator C-Mod
    journal, May 2013


    Benchmarking sheath subgrid boundary conditions for macroscopic-scale simulations
    journal, December 2014


    Spatial proximity effects on the excitation of sheath RF voltages by evanescent slow waves in the ion cyclotron range of frequencies
    journal, January 2017


    Helicon normal modes in Proto-MPEX
    journal, May 2018


    Nonlinear plasma sheath potential in the ASDEX Upgrade 3-strap antenna: a parameter scan
    journal, August 2017


    Experimental Observation of Convective Cell Formation due to a Fast Wave Antenna in the Large Plasma Device
    journal, November 2017


    Analytical solution for capacitive RF sheath
    journal, January 1988


    Numerical solutions of Maxwell's equations in 3D in frequency domain with linear sheath boundary conditions
    journal, August 2019


    Calculation of RF sheath properties from surface wave-fields: a post-processing method
    journal, July 2019