The effect of ECRH on the electron velocity distribution function

Coda, S.; Klimanov, I.; Alberti, S.; Arnoux, G.; Blanchard, P.; Fasoli, A.

doi:10.1088/0741-3335/48/12b/s33

Cited by 18 publications

(27 citation statements)

References 50 publications

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“…Conventional ray-tracing/Fokker-Planck simulations systematically predict a driven current that is more than twice the experimental current (obtained from I p measurements using estimates of the bootstrap fraction) [3][4][5]. Strong evidence of fast electrons anomalous radial transport has been observed in the case of localized ECCD [17,18]. The introduction of a large level of ad-hoc radial transport in Fokker-Planck simulations of fully non-inductive discharges can reduce the calculated current drive to the experimentally measured value.…”

Section: Effect Of Density Fluctuations In Tcvmentioning

confidence: 99%

Effect of density fluctuations on ECCD in ITER and TCV

Decker

Peysson

Coda

2012

EPJ Web of Conferences

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Abstract. Density fluctuations near the edge of tokamak plasmas can affect the propagation of electron cyclotron (EC) waves. In the present paper, the EC wave propagation in a fluctuating equilibrium is determined using the ray-tracing code C3PO. The evolution of the electron distribution function is calculated self-consistently with the EC wave damping using the 3-D Fokker-Planck solver LUKE. The cumulative effect of fluctuations results in a significant broadening of the current profile combined with a fluctuating power deposition profile. This mechanism improves the simulation of fully non-inductive EC discharges in the TCV tokamaks. Predictive simulations for ITER show that density fluctuations could make the stabilization of NTMs in ITER more challenging.

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Section: Effect Of Density Fluctuations In Tcvmentioning

confidence: 99%

Effect of density fluctuations on ECCD in ITER and TCV

Decker

Peysson

Coda

2012

EPJ Web of Conferences

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“…5 The temporal dynamics of the suprathermal population has been investigated in detail with nonperturbative pulsed ECCD experiments combined with coherent averaging of the ECE signals. 9 More recent measurements of oblique ECE have provided evidence of distribution function asymmetries with ECCD. 10 Additionally, the absorption of third-harmonic ECRH on TCV has been shown to be significantly enhanced by the presence of a fast-electron tail.…”

Section: Review Of the Tcv Resultsmentioning

confidence: 99%

Suprathermal electron studies in the TCV tokamak: Design of a tomographic hard-x-ray spectrometer

Gnesin

Coda

Decker

et al. 2008

Review of Scientific Instruments

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Electron cyclotron resonance heating and electron cyclotron current drive, disruptive events, and sawtooth activity are all known to produce suprathermal electrons in fusion devices, motivating increasingly detailed studies of the generation and dynamics of this suprathermal population. Measurements have been performed in the past years in the tokamak à configuration variable ͑TCV͒ tokamak using a single pinhole hard-x-ray ͑HXR͒ camera and electron-cyclotron-emission radiometers, leading, in particular, to the identification of the crucial role of spatial transport in the physics of ECCD. The observation of a poloidal asymmetry in the emitted suprathermal bremsstrahlung radiation motivates the design of a proposed new tomographic HXR spectrometer reported in this paper. The design, which is based on a compact modified Soller collimator concept, is being aided by simulations of tomographic reconstruction. Quantitative criteria have been developed to optimize the design for the greatly variable shapes and positions of TCV plasmas.

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“…In these cases, the presence of non-thermal electrons can enhance the EC emission above thermal levels. Such differences are reasonably well understood [9,10], in contrast to the JET and TFTR "discrepancy".…”

Section: Survey Of Work On the Ts-ece Discrepancymentioning

confidence: 91%

Survey of the TS-ECE Discrepancy and recent investigations in ICRF heated plasmas at Alcator C-Mod

White

Hubbard

Hughes

et al. 2012

EPJ Web of Conferences

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Abstract. This paper reports on a new investigation of the long-standing, unresolved discrepancy between Thomson Scattering (TS) and Electron Cyclotron Emission (ECE) measurements of electron temperature in high temperature tokamak plasmas. At the Alcator C-Mod tokamak, ion cyclotron range of frequency (ICRF) heating is used to produce high temperature conditions where the TS-ECE discrepancy, as observed in the past at JET and TFTR, should appear. Plasmas with T e (0) up to 8 keV are obtained using three different heating scenarios: Ion Cyclotron Resonance Heating (ICRH), ICRF mode conversion heating and a combination of the two heating methods. This is done in order to explore the hypothesis that ICRH-generated fast ions may be related to the discrepancy. In all high temperature cases at C-Mod, we find no evidence for the type of discrepancy reported at JET and TFTR. Here we present the C-Mod results along with a summary of past work on the TS-ECE discrepancy.

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The effect of ECRH on the electron velocity distribution function

Cited by 18 publications

References 50 publications

Effect of density fluctuations on ECCD in ITER and TCV

Effect of density fluctuations on ECCD in ITER and TCV

Suprathermal electron studies in the TCV tokamak: Design of a tomographic hard-x-ray spectrometer

Survey of the TS-ECE Discrepancy and recent investigations in ICRF heated plasmas at Alcator C-Mod

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