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Title: High-resolution kinetic simulations of electron cyclotron heating

Abstract

A parallel solver of the Fokker-Planck equation, coupled with a set of parallel interpretative codes (computing the Electron Cyclotron Emission, X-Ray Emission, and Thomson Scattering spectra for an arbitrary electron distribution function), was written. The code allows the computation of the electron distribution function at much higher resolution in phase-space than it was previously possible. We find this capability to be crucial when simulating ECH in high-performance plasmas. In such plasmas and for normal heating, strong wave damping causes the RF power to be absorbed by the bulk of the distribution function, with negligible production of suprathermal electrons. Strong bulk absorption, however, is associated with the appearance of a new phenomenon: the deformation of the electron distribution at thermal energies. For power deposition near the plasma center, this effect results in the apparent peaking of the central electron temperature (in addition to the temperature increase), and in the discrepancy among the values of the electron temperature measured by different diagnostics (ECE, XRE, TS), reflecting the different energy-range sensitivity of the diagnostics, and the strong energy-dependence of the slope of the bulk distribution function. The deformation of the bulk distribution is governed by a power-density threshold, and increases with the electronmore » temperature.« less

Authors:
 [1]
  1. Asociacion EURATOM/CIEMAT para Fusion, CIEMAT, Av. Complutense 22, 28040 Madrid (Spain)
Publication Date:
OSTI Identifier:
21210485
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: 10.1063/1.59692; (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; CALCULATION METHODS; COMPUTERIZED SIMULATION; DAMPING; DISTRIBUTION FUNCTIONS; ECR HEATING; ELECTRON TEMPERATURE; ELECTRONS; ENERGY ABSORPTION; ENERGY DEPENDENCE; FOKKER-PLANCK EQUATION; INFRARED SPECTRA; ION TEMPERATURE; PHASE SPACE; PLASMA; PLASMA DIAGNOSTICS; PLASMA SIMULATION; RF SYSTEMS; THOMSON SCATTERING

Citation Formats

Krivenski, Vladimir. High-resolution kinetic simulations of electron cyclotron heating. United States: N. p., 1999. Web. doi:10.1063/1.59692.
Krivenski, Vladimir. High-resolution kinetic simulations of electron cyclotron heating. United States. doi:10.1063/1.59692.
Krivenski, Vladimir. Mon . "High-resolution kinetic simulations of electron cyclotron heating". United States. doi:10.1063/1.59692.
@article{osti_21210485,
title = {High-resolution kinetic simulations of electron cyclotron heating},
author = {Krivenski, Vladimir},
abstractNote = {A parallel solver of the Fokker-Planck equation, coupled with a set of parallel interpretative codes (computing the Electron Cyclotron Emission, X-Ray Emission, and Thomson Scattering spectra for an arbitrary electron distribution function), was written. The code allows the computation of the electron distribution function at much higher resolution in phase-space than it was previously possible. We find this capability to be crucial when simulating ECH in high-performance plasmas. In such plasmas and for normal heating, strong wave damping causes the RF power to be absorbed by the bulk of the distribution function, with negligible production of suprathermal electrons. Strong bulk absorption, however, is associated with the appearance of a new phenomenon: the deformation of the electron distribution at thermal energies. For power deposition near the plasma center, this effect results in the apparent peaking of the central electron temperature (in addition to the temperature increase), and in the discrepancy among the values of the electron temperature measured by different diagnostics (ECE, XRE, TS), reflecting the different energy-range sensitivity of the diagnostics, and the strong energy-dependence of the slope of the bulk distribution function. The deformation of the bulk distribution is governed by a power-density threshold, and increases with the electron temperature.},
doi = {10.1063/1.59692},
journal = {AIP Conference Proceedings},
issn = {0094-243X},
number = 1,
volume = 485,
place = {United States},
year = {1999},
month = {9}
}