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Title: A generalized plasma dispersion function for electron damping in tokamak plasmas

Abstract

Radio frequency wave propagation in finite temperature, magnetized plasmas exhibits a wide range of physics phenomena. The plasma response is nonlocal in space and time, and numerous modes are possible with the potential for mode conversions and transformations. Additionally, diffraction effects are important due to finite wavelength and finite-size wave launchers. Multidimensional simulations are required to describe these phenomena, but even with this complexity, the fundamental plasma response is assumed to be the uniform plasma response with the assumption that the local plasma current for a Fourier mode can be described by the Stix conductivity. But, for plasmas with non-uniform magnetic fields, the wave vector itself is nonlocal. When resolved into components perpendicular (k ) and parallel (k ||) to the magnetic field, locality of the parallel component can easily be violated when the wavelength is large. The impact of this inconsistency is that estimates of the wave damping can be incorrect (typically low) due to unresolved resonances. For the case of ion cyclotron damping, this issue has already been addressed by including the effect of parallel magnetic field gradients. In this case, a modified plasma response (Z function) allows resonance broadening even when k || = 0, and thismore » improves the convergence and accuracy of wave simulations. In our paper, we extend this formalism to include electron damping and find improved convergence and accuracy for parameters where electron damping is dominant, such as high harmonic fast wave heating in the NSTX-U tokamak, and helicon wave launch for off-axis current drive in the DIII-D tokamak.« less

Authors:
 [1];  [1];  [2];  [3];  [2];  [3]
  1. XCEL Engineering, Oak Ridge, TN (United States)
  2. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1341560
Grant/Contract Number:  
AC05-00OR22725; AC02-05CH11231
Resource Type:
Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 23; Journal Issue: 10; 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

Citation Formats

Berry, L. A., Jaeger, E. F., Phillips, C. K., Lau, C. H., Bertelli, N., and Green, D. L. A generalized plasma dispersion function for electron damping in tokamak plasmas. United States: N. p., 2016. Web. doi:10.1063/1.4964766.
Berry, L. A., Jaeger, E. F., Phillips, C. K., Lau, C. H., Bertelli, N., & Green, D. L. A generalized plasma dispersion function for electron damping in tokamak plasmas. United States. doi:10.1063/1.4964766.
Berry, L. A., Jaeger, E. F., Phillips, C. K., Lau, C. H., Bertelli, N., and Green, D. L. Fri . "A generalized plasma dispersion function for electron damping in tokamak plasmas". United States. doi:10.1063/1.4964766. https://www.osti.gov/servlets/purl/1341560.
@article{osti_1341560,
title = {A generalized plasma dispersion function for electron damping in tokamak plasmas},
author = {Berry, L. A. and Jaeger, E. F. and Phillips, C. K. and Lau, C. H. and Bertelli, N. and Green, D. L.},
abstractNote = {Radio frequency wave propagation in finite temperature, magnetized plasmas exhibits a wide range of physics phenomena. The plasma response is nonlocal in space and time, and numerous modes are possible with the potential for mode conversions and transformations. Additionally, diffraction effects are important due to finite wavelength and finite-size wave launchers. Multidimensional simulations are required to describe these phenomena, but even with this complexity, the fundamental plasma response is assumed to be the uniform plasma response with the assumption that the local plasma current for a Fourier mode can be described by the Stix conductivity. But, for plasmas with non-uniform magnetic fields, the wave vector itself is nonlocal. When resolved into components perpendicular (k ) and parallel (k ||) to the magnetic field, locality of the parallel component can easily be violated when the wavelength is large. The impact of this inconsistency is that estimates of the wave damping can be incorrect (typically low) due to unresolved resonances. For the case of ion cyclotron damping, this issue has already been addressed by including the effect of parallel magnetic field gradients. In this case, a modified plasma response (Z function) allows resonance broadening even when k || = 0, and this improves the convergence and accuracy of wave simulations. In our paper, we extend this formalism to include electron damping and find improved convergence and accuracy for parameters where electron damping is dominant, such as high harmonic fast wave heating in the NSTX-U tokamak, and helicon wave launch for off-axis current drive in the DIII-D tokamak.},
doi = {10.1063/1.4964766},
journal = {Physics of Plasmas},
number = 10,
volume = 23,
place = {United States},
year = {2016},
month = {10}
}

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Works referenced in this record:

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