Lower hybrid current drive at high density in the multi-pass regime
Assessing the performance of lower hybrid current drive (LHCD) at high density is critical for developing non-inductive current drive systems on future steady-state experiments. Excellent LHCD efficiency has been observed during fully non-inductive operation (η = 2.0 − 2.5 × 10[superscript 19] AW[su...
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| Format: | Article |
| Language: | en_US |
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American Institute of Physics (AIP)
2013
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| Online Access: | http://hdl.handle.net/1721.1/81778 https://orcid.org/0000-0002-9001-5606 https://orcid.org/0000-0003-4432-5504 https://orcid.org/0000-0001-8029-3525 https://orcid.org/0000-0002-7841-9261 https://orcid.org/0000-0002-1620-9680 https://orcid.org/0000-0001-5049-2769 |
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| author | Meneghini, Orso-Maria Cornelio Lau, C. Ma, Y. Harvey, R. W. Schmidt, A. E. Smirnov, A. P. Wilson, J. R. Wallace, Gregory Marriner Faust, Ian Charles Parker, Ronald R. Shiraiwa, Shunichi Baek, Seung Gyou Bonoli, Paul T. Hubbard, Amanda E. Hughes, Jerry W. Labombard, Brian Reinke, Matthew Logan Terry, James L. Whyte, Dennis G. Wright, John C. Wukitch, Stephen James |
| author2 | Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science |
| author_facet | Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science Meneghini, Orso-Maria Cornelio Lau, C. Ma, Y. Harvey, R. W. Schmidt, A. E. Smirnov, A. P. Wilson, J. R. Wallace, Gregory Marriner Faust, Ian Charles Parker, Ronald R. Shiraiwa, Shunichi Baek, Seung Gyou Bonoli, Paul T. Hubbard, Amanda E. Hughes, Jerry W. Labombard, Brian Reinke, Matthew Logan Terry, James L. Whyte, Dennis G. Wright, John C. Wukitch, Stephen James |
| author_sort | Meneghini, Orso-Maria Cornelio |
| collection | MIT |
| description | Assessing the performance of lower hybrid current drive (LHCD) at high density is critical for developing non-inductive current drive systems on future steady-state experiments. Excellent LHCD efficiency has been observed during fully non-inductive operation (η = 2.0 − 2.5 × 10[superscript 19] AW[superscript –1] m[superscript –2] at [¯ over n][subscript e] = 0.5 × 10[superscript 20] m[superscript –3]) on Alcator C-Mod [I. H. Hutchinson et al., Phys. Plasmas1, 1511 (1994)] under conditions (n[subscript e], magnetic field and topology, and LHCD frequency) relevant to ITER [S. Shiraiwa et al., Nucl. Fusion 51, 103024 (2011)]. To extend these results to advanced tokamak regimes with higher bootstrap current fractions on C-Mod, it is necessary to increase [¯ over n][subscript e] to 1.0 − 1.5 × 10[superscript 20] m[superscript −3]. However, the number of current-carrying, non-thermal electrons generated by LHCD drops sharply in diverted configurations at densities that are well below the density limit previously observed on limited tokamaks. In these cases, changes in scrape off layer (SOL)ionization and density profiles are observed during LHCD, indicating that significant power is transferred from the LH waves to the SOL.Fokker-Planck simulations of these discharges utilizing ray tracing and full wave propagation codes indicate that LH waves in the high density, multi-pass absorption regime linger in the plasma edge, and SOL region, where absorption near or outside the LCFS results in the loss of current drive efficiency. Modeling predicts that non-thermal emission increases with stronger single-pass absorption. Experimental data show that increasing T[subscript e] in high density LH discharges results in higher non-thermal electron emission, as predicted by the models. |
| first_indexed | 2024-09-23T16:45:47Z |
| format | Article |
| id | mit-1721.1/81778 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T16:45:47Z |
| publishDate | 2013 |
| publisher | American Institute of Physics (AIP) |
| record_format | dspace |
| spelling | mit-1721.1/817782022-09-29T21:19:03Z Lower hybrid current drive at high density in the multi-pass regime Meneghini, Orso-Maria Cornelio Lau, C. Ma, Y. Harvey, R. W. Schmidt, A. E. Smirnov, A. P. Wilson, J. R. Wallace, Gregory Marriner Faust, Ian Charles Parker, Ronald R. Shiraiwa, Shunichi Baek, Seung Gyou Bonoli, Paul T. Hubbard, Amanda E. Hughes, Jerry W. Labombard, Brian Reinke, Matthew Logan Terry, James L. Whyte, Dennis G. Wright, John C. Wukitch, Stephen James Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology. Department of Nuclear Science and Engineering Massachusetts Institute of Technology. Plasma Science and Fusion Center Wallace, Gregory Marriner Faust, Ian Charles Meneghini, Orso-Maria Cornelio Parker, Ronald R. Shiraiwa, Shunichi Baek, Seung Gyou Bonoli, Paul T. Hubbard, Amanda E. Hughes, Jerry W. Labombard, Brian Lau, C. Ma, Y. Reinke, Matthew Logan Terry, James L. Whyte, Dennis G. Wright, John C. Wukitch, Stephen James Schmidt, A. E. Assessing the performance of lower hybrid current drive (LHCD) at high density is critical for developing non-inductive current drive systems on future steady-state experiments. Excellent LHCD efficiency has been observed during fully non-inductive operation (η = 2.0 − 2.5 × 10[superscript 19] AW[superscript –1] m[superscript –2] at [¯ over n][subscript e] = 0.5 × 10[superscript 20] m[superscript –3]) on Alcator C-Mod [I. H. Hutchinson et al., Phys. Plasmas1, 1511 (1994)] under conditions (n[subscript e], magnetic field and topology, and LHCD frequency) relevant to ITER [S. Shiraiwa et al., Nucl. Fusion 51, 103024 (2011)]. To extend these results to advanced tokamak regimes with higher bootstrap current fractions on C-Mod, it is necessary to increase [¯ over n][subscript e] to 1.0 − 1.5 × 10[superscript 20] m[superscript −3]. However, the number of current-carrying, non-thermal electrons generated by LHCD drops sharply in diverted configurations at densities that are well below the density limit previously observed on limited tokamaks. In these cases, changes in scrape off layer (SOL)ionization and density profiles are observed during LHCD, indicating that significant power is transferred from the LH waves to the SOL.Fokker-Planck simulations of these discharges utilizing ray tracing and full wave propagation codes indicate that LH waves in the high density, multi-pass absorption regime linger in the plasma edge, and SOL region, where absorption near or outside the LCFS results in the loss of current drive efficiency. Modeling predicts that non-thermal emission increases with stronger single-pass absorption. Experimental data show that increasing T[subscript e] in high density LH discharges results in higher non-thermal electron emission, as predicted by the models. United States. Dept. of Energy (Award DE-FC02-99ER54512) United States. Dept. of Energy (Award DE-AC02-09CH11466) 2013-10-25T15:45:49Z 2013-10-25T15:45:49Z 2012-06 2011-12 Article http://purl.org/eprint/type/JournalArticle 1070664X 1089-7674 http://hdl.handle.net/1721.1/81778 Wallace, G. M. et al. “Lower Hybrid Current Drive at High Density in the Multi-pass Regime.” Physics of Plasmas 19.6 (2012): 062505. https://orcid.org/0000-0002-9001-5606 https://orcid.org/0000-0003-4432-5504 https://orcid.org/0000-0001-8029-3525 https://orcid.org/0000-0002-7841-9261 https://orcid.org/0000-0002-1620-9680 https://orcid.org/0000-0001-5049-2769 en_US http://dx.doi.org/10.1063/1.4729734 Physics of Plasmas Creative Commons Attribution-Noncommercial-Share Alike 3.0 http://creativecommons.org/licenses/by-nc/3.0 application/pdf American Institute of Physics (AIP) MIT Web Domain |
| spellingShingle | Meneghini, Orso-Maria Cornelio Lau, C. Ma, Y. Harvey, R. W. Schmidt, A. E. Smirnov, A. P. Wilson, J. R. Wallace, Gregory Marriner Faust, Ian Charles Parker, Ronald R. Shiraiwa, Shunichi Baek, Seung Gyou Bonoli, Paul T. Hubbard, Amanda E. Hughes, Jerry W. Labombard, Brian Reinke, Matthew Logan Terry, James L. Whyte, Dennis G. Wright, John C. Wukitch, Stephen James Lower hybrid current drive at high density in the multi-pass regime |
| title | Lower hybrid current drive at high density in the multi-pass regime |
| title_full | Lower hybrid current drive at high density in the multi-pass regime |
| title_fullStr | Lower hybrid current drive at high density in the multi-pass regime |
| title_full_unstemmed | Lower hybrid current drive at high density in the multi-pass regime |
| title_short | Lower hybrid current drive at high density in the multi-pass regime |
| title_sort | lower hybrid current drive at high density in the multi pass regime |
| url | http://hdl.handle.net/1721.1/81778 https://orcid.org/0000-0002-9001-5606 https://orcid.org/0000-0003-4432-5504 https://orcid.org/0000-0001-8029-3525 https://orcid.org/0000-0002-7841-9261 https://orcid.org/0000-0002-1620-9680 https://orcid.org/0000-0001-5049-2769 |
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