Temperature oscillating regimes in Tore Supra diagnosed by MHD activity

Maget, P.; Imbeaux, F.; Giruzzi, G.; Udintsev, V. S.; Huysmans, G.; Ségui, J. L.; Goniche, M.; Moreau, Ph.; Sabot, R.; Garbet, X.

doi:10.1088/0029-5515/46/8/005

Cited by 50 publications

(58 citation statements)

References 41 publications

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“…Electron fishbones driven only by HFS off-axis (near q = 1) ECRH were observed also in HL-1M tokamak [20]; applying LH waves was found to enhance the fishbone, but only in conjunction with ECRH. Meanwhile, the observation of fishbone oscillations driven by only LH waves has been reported on FTU [7,21,22] and Tore Supra [23,24].…”

Section: Experimental Evidences Of Energetic Electron Driven Fishbonesmentioning

confidence: 99%

Theory and modeling of electron fishbones

et al. 2016

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Internal kink instabilities exhibiting fishbone like behavior have been observed in a variety of experiments where a high energy electron population, generated by strong auxiliary heating and/or current drive systems, was present. After briefly reviewing the experimental evidences of energetic electrons driven fishbones, and the main results of linear and nonlinear theory of electron fishbones, the results of global, self-consistent, nonlinear hybrid MHD-Gyrokinetic simulations will be presented. To this purpose, the extended/hybrid MHD-Gyrokinetic code XHMGC will be used. Linear dynamics analysis will enlighten the effect of considering kinetic thermal ion compressibility and diamagnetic response, and kinetic thermal electrons compressibility, in addition to the energetic electron contribution. Nonlinear saturation and energetic electron transport will also be addressed, making extensive use of Hamiltonian mapping techniques, discussing both centrally peaked and offaxis peaked energetic electron profiles. It will be shown that centrally peaked energetic electron profiles are characterized by resonant excitation and nonlinear response of deeply trapped energetic electrons. On the other side, off-axis peaked energetic electron profiles are characterized by resonant excitation and nonlinear response of barely circulating energetic electrons which experience toroidal precession reversal of their motion.

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Section: Experimental Evidences Of Energetic Electron Driven Fishbonesmentioning

confidence: 99%

Theory and modeling of electron fishbones

et al. 2016

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“…(32) can be obtained from Eqs. (6), (8) and (31), noting that, for resonant particles involved in the δH N L,z dynamics…”

Section: Nonlinear Amplitude Equationmentioning

confidence: 99%

Electron fishbones: theory and experimental evidence

et al. 2007

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We discuss the processes underlying the excitation of fishbone-like internal kink instabilities driven by supra-thermal electrons generated experimentally by different means: Electron Cyclotron Resonance Heating (ECRH) and by Lower Hybrid (LH) power injection. The peculiarity and interest of exciting these electron fishbones by ECRH only or by LH only is also analyzed. Not only the mode stability is explained, but also the transition between steady state nonlinear oscillations to bursting (almost regular) pulsations, as observed in FTU, is interpreted in terms of the LH power input. These results are directly relevant to the investigation of trapped alpha particle interactions with low-frequency MHD modes in burning plasmas: in fact, alpha particles in reactor relevant conditions are characterized by small dimensionless orbits, similarly to electrons; the trapped particle bounce averaged dynamics, meanwhile, depends on energy and not mass.

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“…This instability is likely to be the so-called "electron fishbone" mode observed earlier on DIII-D, FTU, and HL1-M in LHCD and0or ECRH plasmas. [22][23][24][25][26] On Tore Supra, however, it would correspond to the destabilization of the m0n ϭ 201 resistive double-kink mode by barely trapped fast electrons with the energy above 30 keV. The electron fishbone mode can be used as a test bed for the correlation ECE diagnostic.…”

Section: Va Electron Fishbone Mode In Lower Hybrid Current Drive Plmentioning

confidence: 99%

First Results of Correlation Electron Cyclotron Emission on Tore Supra

Udintsev

Goniche

Ségui

et al. 2006

Fusion Science and Technology

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Measurements of electron temperature fluctuations by means of correlation electron cyclotron emission (ECE) diagnostics aid in understanding the nature of the turbulent transport in fusion plasmas. On Tore Supra tokamak, a 32-channel heterodyne ECE radiometer has been upgraded to include two channels for temperature fluctuation measurements. The central frequency of the yttrium iron garnet filter on each channel is remotely monitored by a driver, allowing one to shift the observation volume in the plasma radially. To resolve the fluctuation amplitude of 0.1%, integration times of ;3 s at 1 MHz sampling rate are required for the statistical error level of 0.05%. Together with the 32-channel profile radiometer, correlation ECE is a powerful and unique tool for simultaneous observation of the magnetohydrodynamic phenomena and studies of the plasma transport properties in various heating regimes during long-shot multimegawatt operation. First measurements of temperature fluctuations, of various origins, on Tore Supra (including the observation of the toroidicity-induced Alfvén eigenmodes), as well as a description of the analysis methods used in the data evaluation, are reported in this paper.

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Temperature oscillating regimes in Tore Supra diagnosed by MHD activity

Cited by 50 publications

References 41 publications

Theory and modeling of electron fishbones

Theory and modeling of electron fishbones

Electron fishbones: theory and experimental evidence

First Results of Correlation Electron Cyclotron Emission on Tore Supra

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