Design of the collective Thomson scattering diagnostic for International Thermonuclear Experimental Reactor at the 60 GHz frequency range

Méo, F.; Bindslev, H.; Korsholm, S. B.; Tsakadze, E.L.; Walker, Chris; Woskov, P.; Vayakis, G.

doi:10.1063/1.1788853

Cited by 48 publications

(44 citation statements)

References 2 publications

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“…Indeed, previous feasibility studies [16] have found that such a diagnostic could fulfill the measurement requirements for ITER and that it could be combined with the CTS system foreseen to measure fast ion velocity distributions on ITER [17][18][19]. In preparation for proof-of-principle experiments the CTS receiver at TEXTOR was recently modified for measurements with frequency resolution better than 1 MHz [20] as would be required to demonstrate the ability to resolve cyclotron structure in CTS spectra.…”

Section: Introductionmentioning

confidence: 99%

Principles of fuel ion ratio measurements in fusion plasmas by collective Thomson scattering

Stejner¹,

Nielsen²,

Bindslev³

et al. 2011

Plasma Phys. Control. Fusion

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For certain scattering geometries collective Thomson scattering (CTS) measurements are sensitive to the composition of magnetically confined fusion plasmas. CTS therefore holds the potential to become a new diagnostic for measurements of the fuel ion ratio-i.e. the tritium to deuterium density ratio. Measurements of the fuel ion ratio will be important for plasma control and machine protection in future experiments with burning fusion plasmas. Here we examine the theoretical basis for fuel ion ratio measurements by CTS. We show that the sensitivity to plasma composition is enhanced by the signatures of ion cyclotron motion and ion Bernstein waves which appear for scattering geometries with resolved wave vectors near perpendicular to the magnetic field. We investigate the origin and properties of these features in CTS spectra and give estimates of their relative importance for fuel ion ratio measurements.

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Section: Introductionmentioning

confidence: 99%

Principles of fuel ion ratio measurements in fusion plasmas by collective Thomson scattering

Stejner¹,

Nielsen²,

Bindslev³

et al. 2011

Plasma Phys. Control. Fusion

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“…At relatively large frequency shifts, here roughly beyond ±0.5 GHz, CTS measurements provide information about fast, nonthermal ion populations, e.g. from neutral beam heating [4][5][6][7][8][9][10][11][12][13][14] or from fusion reactions in future experiments with burning plasmas [15][16][17][18][19] . At lower frequency shifts, in the bulk ion region of the spectrum, CTS measurements provide information about thermal ion populations including properties such as the ion temperature and drift a) mspe@fysik.dtu.dk velocity (i.e.…”

mentioning

confidence: 99%

Resolving the bulk ion region of millimeter-wave collective Thomson scattering spectra at ASDEX Upgrade

Stejner

Nielsen

Jacobsen

et al. 2014

Review of Scientific Instruments

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Collective Thomson scattering (CTS) measurements provide information about the composition and velocity distribution of confined ion populations in fusion plasmas. The bulk ion part of the CTS spectrum is dominated by scattering off fluctuations driven by the motion of thermalized ion populations. It thus contains information about the ion temperature, rotation velocity and plasma composition. To resolve the bulk ion region and access this information, we installed a fast acquisition system capable of sampling rates up to 12.5 GS/s in the CTS system at ASDEX Upgrade. CTS spectra with frequency resolution in the range of 1 MHz are then obtained through direct digitization and Fourier analysis of the CTS signal. We here describe the design, calibration and operation of the fast receiver system and give examples of measured bulk ion CTS spectra showing the effects of changing ion temperature, rotation velocity and plasma composition.

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“…As in ITER, in the FTU sub-harmonic scenario the fundamental harmonic layer is located where the beam path is under vacuum. Nevertheless, it is worth noting that in FTU the 1 st harmonic layer is always close to the vacuum vessel wall, in front of the plasma-facing mirror surfaces, even using a high toroidal field such as 7.2 T. On the other side, according to the present design of the CTS system [21,22], the sub-harmonic operations -4 -…”

Section: High Field Scenario With B T T Tmentioning

confidence: 99%

First operations with the new Collective Thomson Scattering diagnostic on the Frascati Tokamak Upgrade device

et al. 2015

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Anomalous emissions were found over the last few years in spectra of Collective Thomson Scattering (CTS) diagnostics in tokamak devices such as TEXTOR, ASDEX and FTU, in addition to real CTS signals. The signal frequency, down-shifted with respect to the probing one, suggested a possible origin in Parametric Decay Instability (PDI) processes correlated with the presence of magnetic islands and occurring for pumping wave power levels well below the threshold predicted by conventional models. A threshold below or close to the Electron Cyclotron Resonance Heating (ECRH) power levels could limit, under certain circumstances, the use of the ECRH in fusion devices. An accurate characterization of the conditions for the occurrence of this phenomenon and of its consequences is thus of primary importance. Exploiting the front-steering configuration available with the real-time launcher, the implementation of a new CTS setup now allows studying these anomalous emission phenomena in FTU under conditions of density and wave 1 Corresponding author.

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Design of the collective Thomson scattering diagnostic for International Thermonuclear Experimental Reactor at the 60 GHz frequency range

Cited by 48 publications

References 2 publications

Principles of fuel ion ratio measurements in fusion plasmas by collective Thomson scattering

Principles of fuel ion ratio measurements in fusion plasmas by collective Thomson scattering

Resolving the bulk ion region of millimeter-wave collective Thomson scattering spectra at ASDEX Upgrade

First operations with the new Collective Thomson Scattering diagnostic on the Frascati Tokamak Upgrade device

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