Predicting high harmonic ion cyclotron heating efficiency in Tokamak plasmas
Abstract
Observations of improved radio frequency (RF) heating efficiency in high-confinement (H-) mode plasmas on the National Spherical Tokamak Experiment (NSTX) are investigated by whole-device linear simulation. We present the first full-wave simulation to couple kinetic physics of the well confined core plasma to the poorly confined scrape-off plasma. The new simulation is used to scan the launched fast-wave spectrum and examine the steady-state electric wave field structure for experimental scenarios corresponding to both reduced, and improved RF heating efficiency. We find that launching toroidal wave-numbers that required for fast-wave propagation excites large amplitude (kVm 1 ) coaxial standing modes in the wave electric field between the confined plasma density pedestal and conducting vessel wall. Qualitative comparison with measurements of the stored plasma energy suggest these modes are a probable cause of degraded heating efficiency. Also, the H-mode density pedestal and fast-wave cutoff within the confined plasma allow for the excitation of whispering gallery type eigenmodes localised to the plasma edge.
- Authors:
-
- ORNL
- XCEL
- Publication Date:
- Research Org.:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF)
- Sponsoring Org.:
- USDOE Office of Science (SC)
- OSTI Identifier:
- 1037019
- DOE Contract Number:
- DE-AC05-00OR22725
- Resource Type:
- Journal Article
- Journal Name:
- Physical Review Letters
- Additional Journal Information:
- Journal Volume: 107; Journal Issue: 14; Journal ID: ISSN 0031-9007
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 43 PARTICLE ACCELERATORS; AMPLITUDES; CYCLOTRONS; EFFICIENCY; ELECTRIC FIELDS; EXCITATION; HARMONICS; HEATING; KINETICS; LAUNCHING; PHYSICS; PLASMA; PLASMA DENSITY; SIMULATION
Citation Formats
Green, David L, Jaeger, E. F., Berry, Lee A, Chen, Guangye, Ryan, Philip Michael, and Canik, John. Predicting high harmonic ion cyclotron heating efficiency in Tokamak plasmas. United States: N. p., 2011.
Web. doi:10.1103/PhysRevLett.107.145001.
Green, David L, Jaeger, E. F., Berry, Lee A, Chen, Guangye, Ryan, Philip Michael, & Canik, John. Predicting high harmonic ion cyclotron heating efficiency in Tokamak plasmas. United States. https://doi.org/10.1103/PhysRevLett.107.145001
Green, David L, Jaeger, E. F., Berry, Lee A, Chen, Guangye, Ryan, Philip Michael, and Canik, John. 2011.
"Predicting high harmonic ion cyclotron heating efficiency in Tokamak plasmas". United States. https://doi.org/10.1103/PhysRevLett.107.145001.
@article{osti_1037019,
title = {Predicting high harmonic ion cyclotron heating efficiency in Tokamak plasmas},
author = {Green, David L and Jaeger, E. F. and Berry, Lee A and Chen, Guangye and Ryan, Philip Michael and Canik, John},
abstractNote = {Observations of improved radio frequency (RF) heating efficiency in high-confinement (H-) mode plasmas on the National Spherical Tokamak Experiment (NSTX) are investigated by whole-device linear simulation. We present the first full-wave simulation to couple kinetic physics of the well confined core plasma to the poorly confined scrape-off plasma. The new simulation is used to scan the launched fast-wave spectrum and examine the steady-state electric wave field structure for experimental scenarios corresponding to both reduced, and improved RF heating efficiency. We find that launching toroidal wave-numbers that required for fast-wave propagation excites large amplitude (kVm 1 ) coaxial standing modes in the wave electric field between the confined plasma density pedestal and conducting vessel wall. Qualitative comparison with measurements of the stored plasma energy suggest these modes are a probable cause of degraded heating efficiency. Also, the H-mode density pedestal and fast-wave cutoff within the confined plasma allow for the excitation of whispering gallery type eigenmodes localised to the plasma edge.},
doi = {10.1103/PhysRevLett.107.145001},
url = {https://www.osti.gov/biblio/1037019},
journal = {Physical Review Letters},
issn = {0031-9007},
number = 14,
volume = 107,
place = {United States},
year = {Sat Jan 01 00:00:00 EST 2011},
month = {Sat Jan 01 00:00:00 EST 2011}
}
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