High-resolution multiwire proportional soft x-ray diagnostic measurements on TCV

Sushkov, A. V.; Андреев, В. В.; Camenen, Y.; Pochelon, A.; Klimanov, I.; Scarabosio, A.; Weisen, H.

doi:10.1063/1.2833822

Cited by 25 publications

(19 citation statements)

References 9 publications

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“…1 together with examples of the DNBI induced CXRS spectra. The sawtooth inversion radius, measured by using a multiwire chamber soft x-ray camera [18] (spatial resolution Á c < 0:05 at the midplane), is also indicated by a vertical dashed line in Figs. 1 and 2.…”

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confidence: 99%

Experimental Evidence of Momentum Transport Induced by an Up-Down Asymmetric Magnetic Equilibrium in Toroidal Plasmas

et al. 2010

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The first experimental evidence of parallel momentum transport generated by the up-down asymmetry of a toroidal plasma is reported. The experiments, conducted in the Tokamak à Configuration Variable, were motivated by the recent theoretical discovery of ion-scale turbulent momentum transport induced by an up-down asymmetry in the magnetic equilibrium. The toroidal rotation gradient is observed to depend on the asymmetry in the outer part of the plasma leading to a variation of the central rotation by a factor of 1.5-2. The direction of the effect and its magnitude are in agreement with theoretical predictions for the eight possible combinations of plasma asymmetry, current, and magnetic field.

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confidence: 99%

Experimental Evidence of Momentum Transport Induced by an Up-Down Asymmetric Magnetic Equilibrium in Toroidal Plasmas

et al. 2010

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“…The BIS analysis is applied to the traces of a multiwire proportional soft X-ray detector (DMPX) located under TCV vacuum vessel and having both high temporal and radial resolutions (200 kHz acquisition frequency, 64 lines-of-sight with 7.9 mm average spacing at TCV midplane) [24], as indicated in figures 1(b). As shown in figure 2(b), the DMPX detector has a detection probability p(ν) ≥ 5% for photons in the range hν = 1.5 − 30 keV with a major peak of sensitivity in the range hν = 1.5 − 6 keV, where ν is the emitted frequency and h is the Planck constant.…”

Section: Methodsmentioning

confidence: 99%

Multiple electron cyclotron power deposition location tracking by break-in-slope analysis in TCV plasmas

Curchod¹,

Felici²,

Pochelon³

et al. 2011

Plasma Phys. Control. Fusion

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Abstract. Modulation of the amplitude of externally injected electron cyclotron (EC) power is a frequent method used to determine the radial power deposition profile in fusion plasmas. There are many tools to analyze the plasma response to the power modulations in quasi-stationary conditions. This paper focuses on the unique ability of the break-in-slope (BIS) method to retrieve a quasi-instantaneous estimate of the power deposition profile at each power step in the modulation, an outcome particularly relevant to track the power deposition location in nonstationary conditions. Here, the BIS analysis method is applied to the signals of a fast and high radial resolution wire-chamber soft X-ray camera in the Tokamakà Configuration Variable (TCV) where the plasma magnetic configuration and thus the EC resonance location are varied during the plasma discharge. As a step to validate this technique before real-time control experiments, the time-varying EC power deposition location of a single beam is successfully monitored by off-line BIS analysis. Simultaneous tracking of two EC beams deposition locations gives promising results.

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“…However, the ECE, Thomson scattering and and Charge Excange Recombination Spectroscopy systems available on TCV can not provide real-time data at this time. We must therefore infer the profiles from diagnostics available in real-time, in the TCV case a set of 14 far-infrared interferometer (FIR) chords [22], 64 soft-X ray chords from the DMPX diagnostic [23] and 4 channels from a single-chord multi-filter X-ray diagnostic (XTe). The method to do this has been named "TENEX" (TE and NE from X-rays).…”

Section: Real-time Estimates Of the Kinetic Profilesmentioning

confidence: 99%

Real-time physics-model-based simulation of the current density profile in tokamak plasmas

et al. 2011

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Abstract.A new paradigm is presented to reconstruct the plasma current density profile in a tokamak in real-time. The traditional method of basing the reconstruction on real-time diagnostics combined with a real-time GradShafranov solver suffers from the difficulty of obtaining reliable internal current profile measurements with sufficient spatial and temporal accuracy to have a complete picture of the profile evolution at all times. A new methodology is proposed in which the plasma current density profile is simulated in real-time by solving the first-principle physics-based equations determining its evolution. Effectively, an interpretative transport simulation similar to those run today in post-plasma shot analysis is performed in real-time. This provides realtime reconstructions of the current density profile with spatial and temporal resolution constrained only by the capabilities of the computational platform used and not by the available diagnostics or the choice of basis functions. The diagnostic measurements available in real-time are used to constrain and improve the accuracy of the simulated profiles. Estimates of other plasma quantities, related to the current density profile, become available in real-time as well. The implementation of the proposed paradigm in the TCV tokamak is discussed, and its successful use in plasma experiments is demonstrated. This framework opens up the possibility of unifying q profile reconstructions across different tokamaks using a common physics model and will support a wealth of applications in which improved real-time knowledge of the plasma state is used for feedback control, disruption avoidance, scenario monitoring, and external disturbance estimation.

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High-resolution multiwire proportional soft x-ray diagnostic measurements on TCV

Cited by 25 publications

References 9 publications

Experimental Evidence of Momentum Transport Induced by an Up-Down Asymmetric Magnetic Equilibrium in Toroidal Plasmas

Experimental Evidence of Momentum Transport Induced by an Up-Down Asymmetric Magnetic Equilibrium in Toroidal Plasmas

Multiple electron cyclotron power deposition location tracking by break-in-slope analysis in TCV plasmas

Real-time physics-model-based simulation of the current density profile in tokamak plasmas

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