Modeling of EAST ICRF antenna performance using the full-wave code TORIC
Access to advanced operating regimes in the EAST tokamak will require a combination of electron-cyclotron resonance heating (ECRH), neutral beam injection (NBI) and ion cyclotron range frequency heating (ICRF), with the addition of lower-hybrid current drive (LHCD) for current profile control. Prior...
| Main Authors: | , , , |
|---|---|
| Other Authors: | |
| Format: | Article |
| Language: | en_US |
| Published: |
American Institute of Physics (AIP)
2017
|
| Online Access: | http://hdl.handle.net/1721.1/109214 https://orcid.org/0000-0002-1620-9680 https://orcid.org/0000-0002-9518-4097 |
| _version_ | 1811094054475137024 |
|---|---|
| author | Edlund, Eric Matthias Bonoli, Paul T Porkolab, Miklos Wukitch, Stephen James |
| author2 | Massachusetts Institute of Technology. Plasma Science and Fusion Center |
| author_facet | Massachusetts Institute of Technology. Plasma Science and Fusion Center Edlund, Eric Matthias Bonoli, Paul T Porkolab, Miklos Wukitch, Stephen James |
| author_sort | Edlund, Eric Matthias |
| collection | MIT |
| description | Access to advanced operating regimes in the EAST tokamak will require a combination of electron-cyclotron resonance heating (ECRH), neutral beam injection (NBI) and ion cyclotron range frequency heating (ICRF), with the addition of lower-hybrid current drive (LHCD) for current profile control. Prior experiments at the EAST tokamak facility have shown relatively weak response of the plasma temperature to application of ICRF heating, with typical coupled power about 2 MW out of 12 MW source. The launched spectrum, at n[subscript φ] = 34 for 0-π -0-π phasing and 27 MHz, is largely inaccessible at line-averaged densities of approximately 2 × 10[superscript 19] m[superscript −3]. However, with variable antenna phasing and frequency, this system has considerable latitude to explore different heating schemes. To develop an ICRF actuator control model, we have used the full-wave code TORIC to explore the physics of ICRF wave propagation in EAST. The results presented from this study use a spectrum analysis using a superposition of nφ spanning −50 to +50. The low density regime typical of EAST plasmas results in a perpendicular wavelength comparable to the minor radius which results in global cavity resonance effects and eigenmode formation when the single-pass absorption is low. This behavior indicates that improved performance can be attained by lowering the peak of the k[subscript ||] spectrum by using π/3 phasing of the 4-strap antenna. Based on prior studies conducted at Alcator C-Mod, this phasing is also expected to have the advantage of nearly divergence-free box currents, which should result in reduced levels of impurity production. Significant enhancements of the loading resistance may be achieved by using low k|| phasing and a combination of magnetic field and frequency to vary the location of the resonance and mode conversion regions. TORIC calculations indicate that the significant power may be channeled to the electrons and deuterium majority. We expect that implementation of these recommendations in EAST will yield substantial improvements in the net absorbed power that will greatly assist in the attempt to access advanced tokamak operating regimes. |
| first_indexed | 2024-09-23T15:54:44Z |
| format | Article |
| id | mit-1721.1/109214 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T15:54:44Z |
| publishDate | 2017 |
| publisher | American Institute of Physics (AIP) |
| record_format | dspace |
| spelling | mit-1721.1/1092142022-09-29T17:01:18Z Modeling of EAST ICRF antenna performance using the full-wave code TORIC Edlund, Eric Matthias Bonoli, Paul T Porkolab, Miklos Wukitch, Stephen James Massachusetts Institute of Technology. Plasma Science and Fusion Center Edlund, Eric Matthias Bonoli, Paul T Porkolab, Miklos Wukitch, Stephen James Access to advanced operating regimes in the EAST tokamak will require a combination of electron-cyclotron resonance heating (ECRH), neutral beam injection (NBI) and ion cyclotron range frequency heating (ICRF), with the addition of lower-hybrid current drive (LHCD) for current profile control. Prior experiments at the EAST tokamak facility have shown relatively weak response of the plasma temperature to application of ICRF heating, with typical coupled power about 2 MW out of 12 MW source. The launched spectrum, at n[subscript φ] = 34 for 0-π -0-π phasing and 27 MHz, is largely inaccessible at line-averaged densities of approximately 2 × 10[superscript 19] m[superscript −3]. However, with variable antenna phasing and frequency, this system has considerable latitude to explore different heating schemes. To develop an ICRF actuator control model, we have used the full-wave code TORIC to explore the physics of ICRF wave propagation in EAST. The results presented from this study use a spectrum analysis using a superposition of nφ spanning −50 to +50. The low density regime typical of EAST plasmas results in a perpendicular wavelength comparable to the minor radius which results in global cavity resonance effects and eigenmode formation when the single-pass absorption is low. This behavior indicates that improved performance can be attained by lowering the peak of the k[subscript ||] spectrum by using π/3 phasing of the 4-strap antenna. Based on prior studies conducted at Alcator C-Mod, this phasing is also expected to have the advantage of nearly divergence-free box currents, which should result in reduced levels of impurity production. Significant enhancements of the loading resistance may be achieved by using low k|| phasing and a combination of magnetic field and frequency to vary the location of the resonance and mode conversion regions. TORIC calculations indicate that the significant power may be channeled to the electrons and deuterium majority. We expect that implementation of these recommendations in EAST will yield substantial improvements in the net absorbed power that will greatly assist in the attempt to access advanced tokamak operating regimes. United States. Department of Energy (contract DE-FC02-01ER54648) 2017-05-19T16:43:32Z 2017-05-19T16:43:32Z 2015-12 Article http://purl.org/eprint/type/ConferencePaper 0094-243X 1551-7616 http://hdl.handle.net/1721.1/109214 Edlund, E. M., P. T. Bonoli, M. Porkolab, and S. J. Wukitch. “Modeling of EAST ICRF Antenna Performance Using the Full-Wave Code TORIC” AIP Conference Proceedings 1689, 060002 (2015) https://orcid.org/0000-0002-1620-9680 https://orcid.org/0000-0002-9518-4097 en_US http://dx.doi.org/10.1063/1.4936500 Creative Commons Attribution-Noncommercial-Share Alike http://creativecommons.org/licenses/by-nc-sa/4.0/ application/pdf American Institute of Physics (AIP) MIT Web Domain |
| spellingShingle | Edlund, Eric Matthias Bonoli, Paul T Porkolab, Miklos Wukitch, Stephen James Modeling of EAST ICRF antenna performance using the full-wave code TORIC |
| title | Modeling of EAST ICRF antenna performance using the full-wave code TORIC |
| title_full | Modeling of EAST ICRF antenna performance using the full-wave code TORIC |
| title_fullStr | Modeling of EAST ICRF antenna performance using the full-wave code TORIC |
| title_full_unstemmed | Modeling of EAST ICRF antenna performance using the full-wave code TORIC |
| title_short | Modeling of EAST ICRF antenna performance using the full-wave code TORIC |
| title_sort | modeling of east icrf antenna performance using the full wave code toric |
| url | http://hdl.handle.net/1721.1/109214 https://orcid.org/0000-0002-1620-9680 https://orcid.org/0000-0002-9518-4097 |
| work_keys_str_mv | AT edlundericmatthias modelingofeasticrfantennaperformanceusingthefullwavecodetoric AT bonolipault modelingofeasticrfantennaperformanceusingthefullwavecodetoric AT porkolabmiklos modelingofeasticrfantennaperformanceusingthefullwavecodetoric AT wukitchstephenjames modelingofeasticrfantennaperformanceusingthefullwavecodetoric |