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Identification of trapped electron modes in frequency fluctuation spectra

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Abstract
Ion temperature gradient (ITG) and trapped electron modes (TEM) are two important micro-instabilities in the plasma core region of fusion devices (r/a <= 0.9). They usually coexist in the same range of spatial scale (around 0.1 < k(perpendicular to)rho(i)<1), which makes their discrimination difficult. To investigate them, one can perform gyrokinetic simulations, transport analysis and phase velocity estimations. In Tore Supra, the identification of trapped electron modes (TEM) is made possible due to measured frequency fluctuation spectra. Indeed, turbulent spectra generally expected to be broad-band, can become narrow in case of TEM turbulence, inducing 'quasi-coherent' (QC) modes named QC-TEM. Therefore the analysis of frequency fluctuation spectra becomes a possible tool to differentiate TEM from ITG. We have found indications that the TEM can have a QC signature by comparing frequency fluctuation spectra from reflectometry measurements, gyrokinetic simulations and synthetic diagnostic results. Then the scope of the analysis of QC-TEM are discussed and an application is shown, namely transitions between TEM turbulence and MHD fluctuations.
Keywords
LOC-SOC, ohmic confinement, reflectometry, MHD, trapped electron mode, micro-instabilities, turbulence, PLASMA, DENSITY, TRANSPORT, REFLECTOMETRY, TORE-SUPRA, TURBULENCE

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Chicago
Arnichand, Hugo, J Citrin, S Hacquin, R Sabot, A Krämer-Flecken, X Garbet, C Bourdelle, et al. 2015. “Identification of Trapped Electron Modes in Frequency Fluctuation Spectra.” Plasma Physics and Controlled Fusion 58 (1).
APA
Arnichand, H., Citrin, J., Hacquin, S., Sabot, R., Krämer-Flecken, A., Garbet, X., Bourdelle, C., et al. (2015). Identification of trapped electron modes in frequency fluctuation spectra. PLASMA PHYSICS AND CONTROLLED FUSION, 58(1).
Vancouver
1.
Arnichand H, Citrin J, Hacquin S, Sabot R, Krämer-Flecken A, Garbet X, et al. Identification of trapped electron modes in frequency fluctuation spectra. PLASMA PHYSICS AND CONTROLLED FUSION. 2015;58(1).
MLA
Arnichand, Hugo et al. “Identification of Trapped Electron Modes in Frequency Fluctuation Spectra.” PLASMA PHYSICS AND CONTROLLED FUSION 58.1 (2015): n. pag. Print.
@article{6998385,
  abstract     = {Ion temperature gradient (ITG) and trapped electron modes (TEM) are two important micro-instabilities in the plasma core region of fusion devices (r/a <= 0.9). They usually coexist in the same range of spatial scale (around 0.1 < k(perpendicular to)rho(i)<1), which makes their discrimination difficult. To investigate them, one can perform gyrokinetic simulations, transport analysis and phase velocity estimations. In Tore Supra, the identification of trapped electron modes (TEM) is made possible due to measured frequency fluctuation spectra. Indeed, turbulent spectra generally expected to be broad-band, can become narrow in case of TEM turbulence, inducing 'quasi-coherent' (QC) modes named QC-TEM. Therefore the analysis of frequency fluctuation spectra becomes a possible tool to differentiate TEM from ITG. We have found indications that the TEM can have a QC signature by comparing frequency fluctuation spectra from reflectometry measurements, gyrokinetic simulations and synthetic diagnostic results. Then the scope of the analysis of QC-TEM are discussed and an application is shown, namely transitions between TEM turbulence and MHD fluctuations.},
  articleno    = {014037},
  author       = {Arnichand, Hugo and Citrin, J and Hacquin, S and Sabot, R and Krämer-Flecken, A and Garbet, X and Bourdelle, C and Clairet, F and Giacalone, JC and Guimaraes-Filho, ZO and Guirlet, R and Hornung, Grégoire and Lebschy, A and Lotte, P and Maget, P and Medvedeva, A and Molina, D and Nikolaeva, V and Prisiazhniuk, D},
  issn         = {0741-3335},
  journal      = {PLASMA PHYSICS AND CONTROLLED FUSION},
  keywords     = {LOC-SOC,ohmic confinement,reflectometry,MHD,trapped electron mode,micro-instabilities,turbulence,PLASMA,DENSITY,TRANSPORT,REFLECTOMETRY,TORE-SUPRA,TURBULENCE},
  language     = {eng},
  number       = {1},
  pages        = {9},
  title        = {Identification of trapped electron modes in frequency fluctuation spectra},
  url          = {http://dx.doi.org/10.1088/0741-3335/58/1/014037},
  volume       = {58},
  year         = {2015},
}

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