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Title: Radio frequency wave interactions with a plasma sheath: The role of wave and plasma sheath impedances

Abstract

Radio frequency (RF) sheaths form near surfaces where plasma and strong RF fields coexist. The effect of these RF sheaths on wave propagation near the boundary can be characterized by an effective sheath impedance that includes both resistive and capacitive contributions describing RF sheath rectification and RF power absorption in the sheath [J. R. Myra and D. A. D'Ippolito, Phys. Plasmas 22, 062507 (2015)]. We define a dimensionless parameter, the ratio of incoming wave impedance to the sheath impedance, which determines the characteristics of the interaction, ranging from quasi-conducting to quasi-insulating, or in the case of matched impedances, to either perfect absorption or a sheath-plasma resonance. A semi-analytical analysis is carried out for electrostatic slow waves in the ion cyclotron range of frequencies. For the propagating slow wave case, where the incident wave is partially reflected, the fraction of power dissipated in the sheath is calculated. For the evanescent slow wave case, which admits a sheath-plasma resonance, an amplification factor is calculated. Using the impedance ratio approach, RF sheath interactions are characterized for a range of RF wave and plasma parameters including plasma density, magnetic field angle with respect to the surface, wave frequency, and wave-vector components tangent to themore » surface. For a particularly interesting example case, results are compared with the rfSOL code [H. Kohno and J. R. Myra, Comput. Phys. Commun. 220, 129 (2017)]. Finally, electromagnetic effects, absent from the semi-analytical analysis, are assessed.« less

Authors:
ORCiD logo [1]; ORCiD logo [2]
  1. Lodestar Research Corporation, Boulder, CO (United States)
  2. Kyushu Inst. of Technology, Iizuka (Japan). Dept. of Mechanical Information Science and Technology
Publication Date:
Research Org.:
Lodestar Research Corp., Boulder, CO (United States); Kyushu Inst. of Technology, Iizuka (Japan)
Sponsoring Org.:
USDOE Office of Science (SC), Fusion Energy Sciences (FES); Japan Society for the Promotion of Science (JSPS)
OSTI Identifier:
1511451
Alternate Identifier(s):
OSTI ID: 1511525
Report Number(s):
LRC-19-179
Journal ID: ISSN 1070-664X; DE-FG02-97ER54392; JP16K18336; DE-AC02-05CH11231
Grant/Contract Number:  
AC05-00OR22725; FG02-97ER54392; AC02-05CH11231; JP16K18336
Resource Type:
Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 26; Journal Issue: 5; 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; electric currents; RF waves; plasma sheaths; tokamaks; electrical properties and parameters

Citation Formats

Myra, J. R., and Kohno, H. Radio frequency wave interactions with a plasma sheath: The role of wave and plasma sheath impedances. United States: N. p., 2019. Web. doi:10.1063/1.5088343.
Myra, J. R., & Kohno, H. Radio frequency wave interactions with a plasma sheath: The role of wave and plasma sheath impedances. United States. doi:10.1063/1.5088343.
Myra, J. R., and Kohno, H. Wed . "Radio frequency wave interactions with a plasma sheath: The role of wave and plasma sheath impedances". United States. doi:10.1063/1.5088343. https://www.osti.gov/servlets/purl/1511451.
@article{osti_1511451,
title = {Radio frequency wave interactions with a plasma sheath: The role of wave and plasma sheath impedances},
author = {Myra, J. R. and Kohno, H.},
abstractNote = {Radio frequency (RF) sheaths form near surfaces where plasma and strong RF fields coexist. The effect of these RF sheaths on wave propagation near the boundary can be characterized by an effective sheath impedance that includes both resistive and capacitive contributions describing RF sheath rectification and RF power absorption in the sheath [J. R. Myra and D. A. D'Ippolito, Phys. Plasmas 22, 062507 (2015)]. We define a dimensionless parameter, the ratio of incoming wave impedance to the sheath impedance, which determines the characteristics of the interaction, ranging from quasi-conducting to quasi-insulating, or in the case of matched impedances, to either perfect absorption or a sheath-plasma resonance. A semi-analytical analysis is carried out for electrostatic slow waves in the ion cyclotron range of frequencies. For the propagating slow wave case, where the incident wave is partially reflected, the fraction of power dissipated in the sheath is calculated. For the evanescent slow wave case, which admits a sheath-plasma resonance, an amplification factor is calculated. Using the impedance ratio approach, RF sheath interactions are characterized for a range of RF wave and plasma parameters including plasma density, magnetic field angle with respect to the surface, wave frequency, and wave-vector components tangent to the surface. For a particularly interesting example case, results are compared with the rfSOL code [H. Kohno and J. R. Myra, Comput. Phys. Commun. 220, 129 (2017)]. Finally, electromagnetic effects, absent from the semi-analytical analysis, are assessed.},
doi = {10.1063/1.5088343},
journal = {Physics of Plasmas},
number = 5,
volume = 26,
place = {United States},
year = {2019},
month = {5}
}

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Works referenced in this record:

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

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journal, November 2017


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journal, June 2006


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Radio-frequency wave interactions with a plasma sheath in oblique-angle magnetic fields using a sheath impedance model
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journal, September 2012


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journal, November 2009


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journal, December 2012


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journal, November 1993


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

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  • Physics of Plasmas, Vol. 20, Issue 8
  • DOI: 10.1063/1.4818991

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

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

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journal, November 2017


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conference, January 2014

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    Works referencing / citing this record:

    Filament-assisted mode conversion in magnetized plasmas
    journal, January 2020

    • Tierens, W.; Zhang, W.; Myra, J. R.
    • Physics of Plasmas, Vol. 27, Issue 1
    • DOI: 10.1063/1.5128070

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