Predicting high harmonic ion cyclotron heating efficiency in Tokamak plasmas

D. L. Green; L. A. Berry; G. Chen; P. M. Ryan; J. M. Canik; E. F. Jaeger

doi:10.1103/PhysRevLett.107.145001

Predicting high harmonic ion cyclotron heating efficiency in Tokamak plasmas

D. L. Green, L. A. Berry, G. Chen, P. M. Ryan, J. M. Canik, E. F. Jaeger

Fusion Energy Division

Research output: Contribution to journal › Article › peer-review

33 Scopus citations

Abstract

Observations of improved radio frequency (rf) heating efficiency in ITER relevant high-confinement (H-)mode plasmas on the National Spherical Tokamak Experiment are investigated by whole-device linear simulation. The steady-state rf electric field is calculated for various antenna spectra and the results examined for characteristics that correlate with observations of improved or reduced rf heating efficiency. We find that launching toroidal wave numbers that give fast-wave propagation in the scrape-off plasma excites large amplitude (∼kVm^-1) coaxial standing modes between the confined plasma density pedestal and conducting vessel wall. Qualitative comparison with measurements of the stored plasma energy suggests that these modes are a probable cause of degraded heating efficiency.

Original language	English
Article number	145001
Journal	Physical Review Letters
Volume	107
Issue number	14
DOIs	https://doi.org/10.1103/PhysRevLett.107.145001
State	Published - Sep 26 2011

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abstract = "Observations of improved radio frequency (rf) heating efficiency in ITER relevant high-confinement (H-)mode plasmas on the National Spherical Tokamak Experiment are investigated by whole-device linear simulation. The steady-state rf electric field is calculated for various antenna spectra and the results examined for characteristics that correlate with observations of improved or reduced rf heating efficiency. We find that launching toroidal wave numbers that give fast-wave propagation in the scrape-off plasma excites large amplitude (∼kVm-1) coaxial standing modes between the confined plasma density pedestal and conducting vessel wall. Qualitative comparison with measurements of the stored plasma energy suggests that these modes are a probable cause of degraded heating efficiency.",

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AU - Berry, L. A.

AU - Chen, G.

AU - Ryan, P. M.

AU - Canik, J. M.

AU - Jaeger, E. F.

PY - 2011/9/26

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N2 - Observations of improved radio frequency (rf) heating efficiency in ITER relevant high-confinement (H-)mode plasmas on the National Spherical Tokamak Experiment are investigated by whole-device linear simulation. The steady-state rf electric field is calculated for various antenna spectra and the results examined for characteristics that correlate with observations of improved or reduced rf heating efficiency. We find that launching toroidal wave numbers that give fast-wave propagation in the scrape-off plasma excites large amplitude (∼kVm-1) coaxial standing modes between the confined plasma density pedestal and conducting vessel wall. Qualitative comparison with measurements of the stored plasma energy suggests that these modes are a probable cause of degraded heating efficiency.

AB - Observations of improved radio frequency (rf) heating efficiency in ITER relevant high-confinement (H-)mode plasmas on the National Spherical Tokamak Experiment are investigated by whole-device linear simulation. The steady-state rf electric field is calculated for various antenna spectra and the results examined for characteristics that correlate with observations of improved or reduced rf heating efficiency. We find that launching toroidal wave numbers that give fast-wave propagation in the scrape-off plasma excites large amplitude (∼kVm-1) coaxial standing modes between the confined plasma density pedestal and conducting vessel wall. Qualitative comparison with measurements of the stored plasma energy suggests that these modes are a probable cause of degraded heating efficiency.

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Predicting high harmonic ion cyclotron heating efficiency in Tokamak plasmas

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