Minority and mode conversion heating in (3He)-H JET plasmas

被引：21

作者：

Van Eester, D. ^{[1
]}

Lerche, E. ^{[1
]}

Johnson, T. J. ^{[2
]}

Hellsten, T. ^{[2
]}

Ongena, J. ^{[1
]}

Mayoral, M-L ^{[3
]}

Frigione, D. ^{[4
]}

Sozzi, C. ^{[5
]}

Calabro, G. ^{[4
]}

Lennholm, M. ^{[6
,7
]}

Beaumont, P. ^{[3
]}

Blackman, T. ^{[3
]}

Brennan, D. ^{[3
]}

Brett, A. ^{[3
]}

Cecconello, M. ^{[8
]}

Coffey, I. ^{[3
]}

Coyne, A. ^{[3
]}

Crombe, K. ^{[9
]}

Czarnecka, A. ^{[10
]}

Felton, R. ^{[3
]}

Johnson, M. Gatu ^{[8
]}

Giroud, C. ^{[3
]}

Gorini, G. ^{[5
]}

Hellesen, C. ^{[8
]}

Jacquet, P. ^{[3
]}

Kazakov, Ye O. ^{[11
]}

Kiptily, V. ^{[3
]}

Knipe, S. ^{[3
]}

Krasilnikov, A. ^{[12
]}

Lin, Y. ^{[13
]}

Maslov, M. ^{[14
]}

Monakhov, I. ^{[3
]}

Noble, C. ^{[3
]}

Nocente, M. ^{[5
]}

Pangioni, L. ^{[3
]}

Proverbio, I. ^{[5
]}

Stamp, M. ^{[3
]}

Studholme, W. ^{[3
]}

Tardocchi, M. ^{[5
]}

Versloot, T. W. ^{[15
]}

Vdovin, V. ^{[16
]}

Whitehurst, A. ^{[3
]}

Wooldridge, E. ^{[3
]}

Zoita, V. ^{[17
]}

机构：

[1] TEC Partner, LPP ERM KMS, Assoc Euratom Belgian State, Brussels, Belgium

[2] KTH, Assoc Euratom VR, Stockholm, Sweden

[3] Euratom CCFE Fus Assoc, Culham Sci Ctr, Abingdon, Oxon, England

[4] Euratom ENEA Fus, CR Frascati, Frascati, Italy

[5] EURATOM ENEA CNR Assoc, Inst Fis Plasma, Milan, Italy

[6] Commiss European Communities, B-1049 Brussels, Belgium

[7] Culham Sci Ctr, EFDA Close Support Unit, Abingdon OX14 3DB, Oxon, England

[8] Uppsala Univ, Assoc EURATOM VR, Uppsala, Sweden

[9] Univ Ghent, Dept Appl Phys, B-9000 Ghent, Belgium

[10] Inst Plasma Phys & Laser Microfus, Warsaw, Poland

[11] Chalmers Univ Technol, Euratom VR Assoc, Gothenburg, Sweden

[12] SRC RF Troitsk Inst Innovating & Fus Res, Troitsk, Russia

[13] MIT Plasma Sci & Fus Ctr, Cambridge, MA 02139 USA

[14] Assoc Euratom Confederat Suisse, CRPP EPFL, CH-1015 Lausanne, Switzerland

[15] EURATOM, FOM Inst Rijnhuizen, Nieuwegein, Netherlands

[16] Nucl Fus Inst, RNC Kurchatov Inst, Moscow, Russia

[17] Assoc EURATOM MEdC, Natl Inst Plasma Phys, Bucharest, Romania

来源：

PLASMA PHYSICS AND CONTROLLED FUSION | 2012年 / 54卷 / 07期

关键词：

ION-CYCLOTRON; WAVE; RESONANCE; TOKAMAK;

D O I：

10.1088/0741-3335/54/7/074009

中图分类号：

O35 [流体力学]; O53 [等离子体物理学];

学科分类号：

070204 ; 080103 ; 080704 ;

摘要：

Radio frequency (RF) heating experiments have recently been conducted in JET (He-3)-H plasmas. This type of plasmas will be used in ITER's non-activated operation phase. Whereas a companion paper in this same PPCF issue will discuss the RF heating scenario's at half the nominal magnetic field, this paper documents the heating performance in (He-3)-H plasmas at full field, with fundamental cyclotron heating of He-3 as the only possible ion heating scheme in view of the foreseen ITER antenna frequency bandwidth. Dominant electron heating with global heating efficiencies between 30% and 70% depending on the He-3 concentration were observed and mode conversion (MC) heating proved to be as efficient as He-3 minority heating. The unwanted presence of both He-4 and D in the discharges gave rise to 2 MC layers rather than a single one. This together with the fact that the location of the high-field side fast wave (FW) cutoff is a sensitive function of the parallel wave number and that one of the locations of the wave confluences critically depends on the He-3 concentration made the interpretation of the results, although more complex, very interesting: three regimes could be distinguished as a function of X[He-3]: (i) a regime at low concentration (X[He-3] < 1.8%) at which ion cyclotron resonance frequency (ICRF) heating is efficient, (ii) a regime at intermediate concentrations (1.8 < X[He-3] < 5%) in which the RF performance is degrading and ultimately becoming very poor, and finally (iii) a good heating regime at He-3 concentrations beyond 6%. In this latter regime, the heating efficiency did not critically depend on the actual concentration while at lower concentrations (X[He-3] < 4%) a bigger excursion in heating efficiency is observed and the estimates differ somewhat from shot to shot, also depending on whether local or global signals are chosen for the analysis. The different dynamics at the various concentrations can be traced back to the presence of 2 MC layers and their associated FW cutoffs residing inside the plasma at low He-3 concentration. One of these layers is approaching and crossing the low-field side plasma edge when 1.8 < X[He-3] < 5%. Adopting a minimization procedure to correlate the MC positions with the plasma composition reveals that the different behaviors observed are due to contamination of the plasma. Wave modeling not only supports this interpretation but also shows that moderate concentrations of D-like species significantly alter the overall wave behavior in He-3-H plasmas. Whereas numerical modeling yields quantitative information on the heating efficiency, analytical work gives a good description of the dominant underlying wave interaction physics.

引用

页数：19

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