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Title: Radio frequency CD by LH waves in the reversed field experiment

Abstract

We present a feasibility study for the active control of the poloidal current density profile in the RFX (reversed field pinch) experiment using radio frequency in the range of lower hybrid waves. The main goal of the rf current drive is to reduce the magnetic fluctuations and the magnetic stochasticity, so as to improve the energy confinement. The compelling constraints of accessibility and damping of the slow waves due to the present and extrapolated RFX plasma parameters are investigated; they have been used to fix the frequency ({approx_equal}1.3 GHz) and the best n{sub parallel} values ({approx_equal}8), and therefore the antenna size (Grill). A modified version of the FELICE code, which takes into account the strong shear of the magnetic field of the RFP plasmas, has been developed and used to estimate the antenna-plasma coupling: the reflected power for the proposed antenna is found to be less than 30% for a quite wide range of plasma parameters. In order to estimate the current drive profile and efficiency a one dimensional Fokker-Planck code has been used: an additional crucial contribution to the driven current is due to the enhancement of the plasma conductivity as consequence of the suprathermal electron population increase. Althoughmore » the total estimated CD efficiency is promising, the rf-power required to drive the current necessary to produce a significant reduction of the magnetic fluctuations is found to be in the MW range.« less

Authors:
 [1];  [2];  [3]
  1. Consorzio RFX, Corso Stati Uniti 4, 35127 Padova (Italy)
  2. (Italy)
  3. Maz Planck Institute fuer Plasmaphysik, EURATOM Ass., D-85748 Garching (Germany)
Publication Date:
OSTI Identifier:
21210452
Resource Type:
Journal Article
Journal Name:
AIP Conference Proceedings
Additional Journal Information:
Journal Volume: 485; Journal Issue: 1; Conference: 13. topical conference on radio frequency power in plasmas, Annapolis, MD (United States), 12-14 Apr 1999; Other Information: DOI: 10.1063/1.59731; (c) 1999 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0094-243X
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ANTENNAS; COUPLING; CURRENT DENSITY; DAMPING; ELECTRIC CURRENTS; ELECTRONS; FLUCTUATIONS; FOKKER-PLANCK EQUATION; GHZ RANGE; LOWER HYBRID CURRENT DRIVE; LOWER HYBRID HEATING; MAGNETIC FIELDS; PLASMA; PLASMA CONFINEMENT; PLASMA DENSITY; REVERSE-FIELD PINCH; RF SYSTEMS; RFX DEVICE; SHEAR

Citation Formats

Bilato, R., Istituto Nazionale di Fisica della Materia, Padova, and Brambilla, M. Radio frequency CD by LH waves in the reversed field experiment. United States: N. p., 1999. Web. doi:10.1063/1.59731.
Bilato, R., Istituto Nazionale di Fisica della Materia, Padova, & Brambilla, M. Radio frequency CD by LH waves in the reversed field experiment. United States. doi:10.1063/1.59731.
Bilato, R., Istituto Nazionale di Fisica della Materia, Padova, and Brambilla, M. Mon . "Radio frequency CD by LH waves in the reversed field experiment". United States. doi:10.1063/1.59731.
@article{osti_21210452,
title = {Radio frequency CD by LH waves in the reversed field experiment},
author = {Bilato, R. and Istituto Nazionale di Fisica della Materia, Padova and Brambilla, M.},
abstractNote = {We present a feasibility study for the active control of the poloidal current density profile in the RFX (reversed field pinch) experiment using radio frequency in the range of lower hybrid waves. The main goal of the rf current drive is to reduce the magnetic fluctuations and the magnetic stochasticity, so as to improve the energy confinement. The compelling constraints of accessibility and damping of the slow waves due to the present and extrapolated RFX plasma parameters are investigated; they have been used to fix the frequency ({approx_equal}1.3 GHz) and the best n{sub parallel} values ({approx_equal}8), and therefore the antenna size (Grill). A modified version of the FELICE code, which takes into account the strong shear of the magnetic field of the RFP plasmas, has been developed and used to estimate the antenna-plasma coupling: the reflected power for the proposed antenna is found to be less than 30% for a quite wide range of plasma parameters. In order to estimate the current drive profile and efficiency a one dimensional Fokker-Planck code has been used: an additional crucial contribution to the driven current is due to the enhancement of the plasma conductivity as consequence of the suprathermal electron population increase. Although the total estimated CD efficiency is promising, the rf-power required to drive the current necessary to produce a significant reduction of the magnetic fluctuations is found to be in the MW range.},
doi = {10.1063/1.59731},
journal = {AIP Conference Proceedings},
issn = {0094-243X},
number = 1,
volume = 485,
place = {United States},
year = {1999},
month = {9}
}