skip to main content

SciTech ConnectSciTech Connect

Title: Interaction between the lower hybrid wave and density fluctuations in the scrape-off layer

In the present paper, the perturbation of the launched power spectrum of the Lower Hybrid wave at the separatrix by electron density fluctuations in the scrape-off layer is investigated. Considering a slab geometry with magnetic field lines parallel to the toroidal direction, the full wave equation is solved using Comsol Multiphysics® for a fully active multi-junction like LH antenna made of two modules. When electron density fluctuations are incorporated in the dielectric tensor over a thin perturbed layer in front of the grill, it is shown that the power spectrum may be strongly modified from the antenna mouth to the plasma separatrix as the wave propagates. The diffraction effect leads to the appearance of multiple satellite lobes with randomly varying positions, a feature consistent with the recently developed model that has been applied successfully to high density discharges on the Tokamak Tore Supra corresponding to the large spectral gap regime [Decker J. et al. Phys. Plasma 21 (2014) 092504]. The perturbation is found to be maximum for the Fourier components of the fluctuating spectrum in the vicinity of the launched LH wavelength.
Authors:
 [1] ; ;  [2] ;  [3]
  1. CEA, IRFM, 13108 Saint Paul-lez-Durance (France)
  2. AUB, Bliss Street (Lebanon)
  3. EPFL, CRPP (Switzerland)
Publication Date:
OSTI Identifier:
22496221
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1689; Journal Issue: 1; Conference: 21. topical conference on radio frequency power in plasmas, Lake Arrowhead, CA (United States), 27-29 Apr 2015; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ANTENNAS; CONNECTORS; DIELECTRIC TENSOR; DIFFRACTION; DISTURBANCES; ELECTRON DENSITY; FLUCTUATIONS; GEOMETRY; INTERACTIONS; LOWER HYBRID CURRENT DRIVE; LOWER HYBRID HEATING; MAGNETIC FIELDS; PERTURBATION THEORY; PLASMA; PLASMA SCRAPE-OFF LAYER; SPECTRA; TORE SUPRA TOKAMAK; WAVELENGTHS