MIT Libraries logoDSpace@MIT

MIT
View Item 
  • DSpace@MIT Home
  • MIT Open Access Articles
  • MIT Open Access Articles
  • View Item
  • DSpace@MIT Home
  • MIT Open Access Articles
  • MIT Open Access Articles
  • View Item
JavaScript is disabled for your browser. Some features of this site may not work without it.

External excitation of a short-wavelength fluctuation in the Alcator C-Mod edge plasma and its relationship to the quasi-coherent mode

Author(s)
Parker, R. R.; Davis, E.; Golfinopoulos, Theodore; Labombard, Brian; Burke, William M.; Granetz, Robert S.; Greenwald, Martin J.; Irby, James Henderson; Leccacorvi, Rick; Marmar, Earl S.; Parkin, William C.; Porkolab, Miklos; Terry, James L.; Vieira, Rui F.; Wolfe, Stephen M.; ... Show more Show less
Thumbnail
DownloadPorkolab_External excitation.pdf (4.872Mb)
OPEN_ACCESS_POLICY

Open Access Policy

Creative Commons Attribution-Noncommercial-Share Alike

Terms of use
Creative Commons Attribution-Noncommercial-Share Alike http://creativecommons.org/licenses/by-nc-sa/4.0/
Metadata
Show full item record
Abstract
A novel “Shoelace” antenna has been used to inductively excite a short-wavelength edge fluctuation in a tokamak boundary layer for the first time. The principal design parameters, k[subscript ⊥] = 1.5 ± 0.1 cm[superscript −1] and 45 < f < 300 kHz, match the Quasi-Coherent Mode (QCM, k[subscript ⊥] ∼ 1.5 cm[superscript −1], f ∼ 50−150 kHz) in Alcator C-Mod, responsible for exhausting impurities in the steady-state, ELM-free Enhanced D[subscript α] H-mode. In H-mode, whether or not there is a QCM, the antenna drives coherent, field-aligned perturbations in density, [˜ over n][subscript e], and field, [˜ over B][subscript θ], which are guided by field lines, propagate in the electron diamagnetic drift direction, and exhibit a weakly damped (γ/ω[subscript 0] ∼ 5%−10%) resonance near the natural QCM frequency. This result is significant, offering the possibility that externally driven modes may be used to enhance particle transport. In L-mode, the antenna drives only a non-resonant [˜ over B][subscript θ] response. The facts that the driven mode has the same wave number and propagation direction as the QCM, and is resonant at the QCM frequency, suggest the antenna may couple to this mode, which we have shown elsewhere to be predominantly drift-mode-like [B. LaBombard et al., Phys. Plasmas 21, 056108 (2014)].
Date issued
2014-05
URI
http://hdl.handle.net/1721.1/88555
Department
Massachusetts Institute of Technology. Department of Physics; Massachusetts Institute of Technology. Plasma Science and Fusion Center
Journal
Physics of Plasmas
Publisher
American Institute of Physics (AIP)
Citation
Golfinopoulos, T., B. LaBombard, R. R. Parker, W. Burke, E. Davis, R. Granetz, M. Greenwald, et al. “External Excitation of a Short-Wavelength Fluctuation in the Alcator C-Mod Edge Plasma and Its Relationship to the Quasi-Coherent Mode.” Phys. Plasmas 21, no. 5 (May 2014): 056111.
Version: Author's final manuscript
ISSN
1070-664X
1089-7674

Collections
  • MIT Open Access Articles

Browse

All of DSpaceCommunities & CollectionsBy Issue DateAuthorsTitlesSubjectsThis CollectionBy Issue DateAuthorsTitlesSubjects

My Account

Login

Statistics

OA StatisticsStatistics by CountryStatistics by Department
MIT Libraries
PrivacyPermissionsAccessibilityContact us
MIT
Content created by the MIT Libraries, CC BY-NC unless otherwise noted. Notify us about copyright concerns.