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Title: Identification of waves in the lower-hybrid frequency range in the scrape-off layer plasma of Alcator C-Mod

Journal Article · · Nuclear Fusion
 [1];  [2];  [2];  [2];  [1];  [2];  [2];  [2];  [2];  [2];
  1. University of Tokyo, Kashiwa (Japan)
  2. Massachusetts Institute of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center
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We report polarization resolved measurements of the parallel refractive index $$N_∥≡ck_∥/w$$ of the driven RF waves in the lower hybrid (LH) range of frequencies are performed using arrays of RF magnetic probes in the scrape-off layer plasma of Alcator C-Mod. The measured $$N_∥$$ of the RF magnetic field component parallel to the background magnetic field is about –1.6, which corresponds to the peak of the launched LH $$N_∥$$ spectrum. Based on the wave dispersion relationship, this wave is identified as the LH slow wave. On the other hand, the RF magnetic field component perpendicular to the magnetic field is found to have a lower $$N_∥$$ of –1.2, and is detected only near the last closed flux surface. This wave is identified as the LH fast wave generated by slow-fast wave mode conversion.

Research Organization:
Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Fusion Energy Sciences (FES)
Grant/Contract Number:
FC02-99ER54512
OSTI ID:
1535578
Alternate ID(s):
OSTI ID: 1335184
Journal Information:
Nuclear Fusion, Vol. 57, Issue 3; ISSN 0029-5515
Publisher:
IOP ScienceCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 2 works
Citation information provided by
Web of Science

References (10)

Linear Theory of Lower Hybrid Heating journal January 1984
Lower hybrid current drive at high density in Alcator C-Mod journal July 2011
Current drive at plasma densities required for thermonuclear reactors journal August 2010
Lower hybrid current drive at high density on Tore Supra journal February 2013
Experimental investigations of LHW–plasma coupling and current drive related to achieving H-mode plasmas in EAST journal October 2013
Progress towards steady-state regimes in Alcator C-Mod journal October 2013
Lower hybrid current drive efficiency in tokamaks and wave scattering by density fluctuations at the plasma edge journal November 2011
Electrostatic potential variations along flux surfaces in stellarators journal April 2015
Lower hybrid wave edge power loss quantification on the Alcator C-Mod tokamak journal May 2016
Measurements of the parallel wavenumber of lower hybrid waves in the scrape-off layer of a high-density tokamak journal May 2016

Cited By (1)

Modified propagation path and expanded coupling regime of lower hybrid fast wave by n ∥-upshift via wave scattering in VEST journal January 2019

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70 PLASMA PHYSICS AND FUSION TECHNOLOGY
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lower hybrid wave
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