Particle-in-cell simulation of parasitic absorption of lower hybrid power in edge plasmas of tokamaks

Karin Rantamäki, Timo Pättikangas, Seppo Karttunen, X Litaudon, D Moreau, P Bibet, A Ekedahl

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Abstract

In lower hybrid (LH) current drive experiments at Tore Supra and Tokamak de Varennes (TdeV), hot spots and the generation of impurities have been observed. Melting of the grill mouth has also occurred in LH current drive experiments. A possible explanation for these observations is parasitic absorption of the short-wavelength part of the LH spectrum close to the grill mouth.

In this work, we investigate the parasitic absorption of the LH power in the edge plasma of Tore Supra and JET with particle-in-cell (PIC) simulations. The LH spectra are calculated with the SWAN coupling code and used in the self-consistent electrostatic PIC code XPDP2 which calculates the absorption.

The absorption was calculated for different edge densities and density scale lengths when the coupled LH power densities varied between 25 MW m-2 and 50 MW m-2. The high-n|| part of the LH spectrum was found to be absorbed near the edge within a few millimetres. The absorbed power density varied from 65 kW m-2 to 420 kW m-2 which corresponds to 0.2-0.8% of the coupled power. In an edge plasma having a temperature of 25 eV, the maximum energies of the fast electrons generated by the parasitic absorption were between 0.4 keV and 1.6 keV.
Original languageEnglish
Pages (from-to)1125-1133
Number of pages9
JournalPlasma Physics and Controlled Fusion
Volume41
Issue number9
DOIs
Publication statusPublished - 1999
MoE publication typeA1 Journal article-refereed

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Plasmas
cells
mouth
Electrostatics
Melting
simulation
Experiments
Impurities
radiant flux density
Wavelength
Electrons
Temperature
melting
electrostatics
impurities
wavelengths
electrons
temperature
energy

Cite this

Rantamäki, Karin ; Pättikangas, Timo ; Karttunen, Seppo ; Litaudon, X ; Moreau, D ; Bibet, P ; Ekedahl, A. / Particle-in-cell simulation of parasitic absorption of lower hybrid power in edge plasmas of tokamaks. In: Plasma Physics and Controlled Fusion. 1999 ; Vol. 41, No. 9. pp. 1125-1133.
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abstract = "In lower hybrid (LH) current drive experiments at Tore Supra and Tokamak de Varennes (TdeV), hot spots and the generation of impurities have been observed. Melting of the grill mouth has also occurred in LH current drive experiments. A possible explanation for these observations is parasitic absorption of the short-wavelength part of the LH spectrum close to the grill mouth.In this work, we investigate the parasitic absorption of the LH power in the edge plasma of Tore Supra and JET with particle-in-cell (PIC) simulations. The LH spectra are calculated with the SWAN coupling code and used in the self-consistent electrostatic PIC code XPDP2 which calculates the absorption.The absorption was calculated for different edge densities and density scale lengths when the coupled LH power densities varied between 25 MW m-2 and 50 MW m-2. The high-n|| part of the LH spectrum was found to be absorbed near the edge within a few millimetres. The absorbed power density varied from 65 kW m-2 to 420 kW m-2 which corresponds to 0.2-0.8{\%} of the coupled power. In an edge plasma having a temperature of 25 eV, the maximum energies of the fast electrons generated by the parasitic absorption were between 0.4 keV and 1.6 keV.",
author = "Karin Rantam{\"a}ki and Timo P{\"a}ttikangas and Seppo Karttunen and X Litaudon and D Moreau and P Bibet and A Ekedahl",
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Particle-in-cell simulation of parasitic absorption of lower hybrid power in edge plasmas of tokamaks. / Rantamäki, Karin; Pättikangas, Timo; Karttunen, Seppo; Litaudon, X; Moreau, D; Bibet, P; Ekedahl, A.

In: Plasma Physics and Controlled Fusion, Vol. 41, No. 9, 1999, p. 1125-1133.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Particle-in-cell simulation of parasitic absorption of lower hybrid power in edge plasmas of tokamaks

AU - Rantamäki, Karin

AU - Pättikangas, Timo

AU - Karttunen, Seppo

AU - Litaudon, X

AU - Moreau, D

AU - Bibet, P

AU - Ekedahl, A

PY - 1999

Y1 - 1999

N2 - In lower hybrid (LH) current drive experiments at Tore Supra and Tokamak de Varennes (TdeV), hot spots and the generation of impurities have been observed. Melting of the grill mouth has also occurred in LH current drive experiments. A possible explanation for these observations is parasitic absorption of the short-wavelength part of the LH spectrum close to the grill mouth.In this work, we investigate the parasitic absorption of the LH power in the edge plasma of Tore Supra and JET with particle-in-cell (PIC) simulations. The LH spectra are calculated with the SWAN coupling code and used in the self-consistent electrostatic PIC code XPDP2 which calculates the absorption.The absorption was calculated for different edge densities and density scale lengths when the coupled LH power densities varied between 25 MW m-2 and 50 MW m-2. The high-n|| part of the LH spectrum was found to be absorbed near the edge within a few millimetres. The absorbed power density varied from 65 kW m-2 to 420 kW m-2 which corresponds to 0.2-0.8% of the coupled power. In an edge plasma having a temperature of 25 eV, the maximum energies of the fast electrons generated by the parasitic absorption were between 0.4 keV and 1.6 keV.

AB - In lower hybrid (LH) current drive experiments at Tore Supra and Tokamak de Varennes (TdeV), hot spots and the generation of impurities have been observed. Melting of the grill mouth has also occurred in LH current drive experiments. A possible explanation for these observations is parasitic absorption of the short-wavelength part of the LH spectrum close to the grill mouth.In this work, we investigate the parasitic absorption of the LH power in the edge plasma of Tore Supra and JET with particle-in-cell (PIC) simulations. The LH spectra are calculated with the SWAN coupling code and used in the self-consistent electrostatic PIC code XPDP2 which calculates the absorption.The absorption was calculated for different edge densities and density scale lengths when the coupled LH power densities varied between 25 MW m-2 and 50 MW m-2. The high-n|| part of the LH spectrum was found to be absorbed near the edge within a few millimetres. The absorbed power density varied from 65 kW m-2 to 420 kW m-2 which corresponds to 0.2-0.8% of the coupled power. In an edge plasma having a temperature of 25 eV, the maximum energies of the fast electrons generated by the parasitic absorption were between 0.4 keV and 1.6 keV.

U2 - 10.1088/0741-3335/41/9/305

DO - 10.1088/0741-3335/41/9/305

M3 - Article

VL - 41

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EP - 1133

JO - Plasma Physics and Controlled Fusion

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SN - 0741-3335

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ER -