Absorption of lower hybrid waves in the scrape off layer of a diverted tokamak
The goal of the Lower Hybrid Current Drive (LHCD) system on the Alcator C-Mod tokamak [ Hutchinson et al., Phys. Plasmas 1, 1511 (1994) ] is to investigate current profile control under plasma conditions relevant to future tokamak experiments. Experimental observations of a LHCD “density limit” for...
| Main Authors: | , , , , , , , , , , , , , |
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| Format: | Article |
| Language: | en_US |
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American Institute of Physics
2011
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| Online Access: | http://hdl.handle.net/1721.1/67355 https://orcid.org/0000-0002-9001-5606 https://orcid.org/0000-0003-4432-5504 https://orcid.org/0000-0002-7841-9261 https://orcid.org/0000-0002-1620-9680 |
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| author | Wallace, Gregory Marriner Parker, Ronald R. Bonoli, Paul T. Hubbard, Amanda E. Hughes, Jerry W. LaBombard, Brian Meneghini, Orso-Maria Cornelio Schmidt, Andrea Elizabeth Shiraiwa, Shunichi Whyte, Dennis G. Wright, John C. Wukitch, Stephen James Smirnov, A. P. Wilson, J. R. |
| 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 Wallace, Gregory Marriner Parker, Ronald R. Bonoli, Paul T. Hubbard, Amanda E. Hughes, Jerry W. LaBombard, Brian Meneghini, Orso-Maria Cornelio Schmidt, Andrea Elizabeth Shiraiwa, Shunichi Whyte, Dennis G. Wright, John C. Wukitch, Stephen James Smirnov, A. P. Wilson, J. R. |
| author_sort | Wallace, Gregory Marriner |
| collection | MIT |
| description | The goal of the Lower Hybrid Current Drive (LHCD) system on the Alcator C-Mod tokamak [ Hutchinson et al., Phys. Plasmas 1, 1511 (1994) ] is to investigate current profile control under plasma conditions relevant to future tokamak experiments. Experimental observations of a LHCD “density limit” for C-Mod are presented in this paper. Bremsstrahlung emission from relativistic fast electrons in the core plasma drops suddenly above line averaged densities of 10[superscript 20] m[superscript −3] (ω/ω[subscript LH] ~ 3–4), well below the density limit previously observed on other experiments (ω/ωLH ∼ 2). Electric currents flowing through the scrape off layer (SOL) between the inner and outer divertors increase dramatically across the same density range that the core bremsstrahlung emission drops precipitously. These experimental x-ray data are compared to both conventional modeling, which gives poor agreement with experiment above the density limit and a model including collisional absorption in the SOL, which dramatically improves agreement with experiment above the observed density limit. These results show that strong absorption of LH waves in the SOL is possible on a high density tokamak and the SOL must be included in simulations of LHCD at high density. |
| first_indexed | 2024-09-23T16:51:50Z |
| format | Article |
| id | mit-1721.1/67355 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T16:51:50Z |
| publishDate | 2011 |
| publisher | American Institute of Physics |
| record_format | dspace |
| spelling | mit-1721.1/673552022-09-29T21:58:19Z Absorption of lower hybrid waves in the scrape off layer of a diverted tokamak Wallace, Gregory Marriner Parker, Ronald R. Bonoli, Paul T. Hubbard, Amanda E. Hughes, Jerry W. LaBombard, Brian Meneghini, Orso-Maria Cornelio Schmidt, Andrea Elizabeth Shiraiwa, Shunichi Whyte, Dennis G. Wright, John C. Wukitch, Stephen James Smirnov, A. P. Wilson, J. R. 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 Whyte, Dennis G. Wallace, Gregory Marriner Parker, Ronald R. Bonoli, Paul T. Hubbard, Amanda E. Hughes, Jerry W. LaBombard, Brian Meneghini, Orso-Maria Cornelio Schmidt, Andrea Elizabeth Shiraiwa, Shunichi Whyte, Dennis G. Wright, John C. Wukitch, Stephen James Harvey, R. W. The goal of the Lower Hybrid Current Drive (LHCD) system on the Alcator C-Mod tokamak [ Hutchinson et al., Phys. Plasmas 1, 1511 (1994) ] is to investigate current profile control under plasma conditions relevant to future tokamak experiments. Experimental observations of a LHCD “density limit” for C-Mod are presented in this paper. Bremsstrahlung emission from relativistic fast electrons in the core plasma drops suddenly above line averaged densities of 10[superscript 20] m[superscript −3] (ω/ω[subscript LH] ~ 3–4), well below the density limit previously observed on other experiments (ω/ωLH ∼ 2). Electric currents flowing through the scrape off layer (SOL) between the inner and outer divertors increase dramatically across the same density range that the core bremsstrahlung emission drops precipitously. These experimental x-ray data are compared to both conventional modeling, which gives poor agreement with experiment above the density limit and a model including collisional absorption in the SOL, which dramatically improves agreement with experiment above the observed density limit. These results show that strong absorption of LH waves in the SOL is possible on a high density tokamak and the SOL must be included in simulations of LHCD at high density. United States. Dept. of Energy (contract DE-FC02-99ER54512) United States. Dept. of Energy (contract DE-AC02-76CH03073) 2011-12-02T19:15:30Z 2011-12-02T19:15:30Z 2010-08 2010-02 Article http://purl.org/eprint/type/JournalArticle 1070-664X 1089-7674 http://hdl.handle.net/1721.1/67355 Wallace, G. M. et al. “Absorption of Lower Hybrid Waves in the Scrape Off Layer of a Diverted Tokamak.” Physics of Plasmas 17.8 (2010) https://orcid.org/0000-0002-9001-5606 https://orcid.org/0000-0003-4432-5504 https://orcid.org/0000-0002-7841-9261 https://orcid.org/0000-0002-1620-9680 en_US http://dx.doi.org/10.1063/1.3465662 Physics of Plasmas Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Institute of Physics AIP |
| spellingShingle | Wallace, Gregory Marriner Parker, Ronald R. Bonoli, Paul T. Hubbard, Amanda E. Hughes, Jerry W. LaBombard, Brian Meneghini, Orso-Maria Cornelio Schmidt, Andrea Elizabeth Shiraiwa, Shunichi Whyte, Dennis G. Wright, John C. Wukitch, Stephen James Smirnov, A. P. Wilson, J. R. Absorption of lower hybrid waves in the scrape off layer of a diverted tokamak |
| title | Absorption of lower hybrid waves in the scrape off layer of a diverted tokamak |
| title_full | Absorption of lower hybrid waves in the scrape off layer of a diverted tokamak |
| title_fullStr | Absorption of lower hybrid waves in the scrape off layer of a diverted tokamak |
| title_full_unstemmed | Absorption of lower hybrid waves in the scrape off layer of a diverted tokamak |
| title_short | Absorption of lower hybrid waves in the scrape off layer of a diverted tokamak |
| title_sort | absorption of lower hybrid waves in the scrape off layer of a diverted tokamak |
| url | http://hdl.handle.net/1721.1/67355 https://orcid.org/0000-0002-9001-5606 https://orcid.org/0000-0003-4432-5504 https://orcid.org/0000-0002-7841-9261 https://orcid.org/0000-0002-1620-9680 |
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