Electric Probes in Tokamaks: Experience in Tore Supra

Gunn, J.; Pascal, J.-Y.; Saint‐Laurent, F.; Gil, C.

doi:10.1002/ctpp.201000074

Cited by 22 publications

(13 citation statements)

References 24 publications

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“…The issue concerning the effective collection area is addressed by comparing the time averaged profiles of saturation current collected by a rake probe with the same profiles collected by a Tunnel probe, which presents a geometry designed to cancel any sheath expansion around the collector. 28 The data collected over a wide range of plasma parameters suggest that the effective collection area of small pines varies by a factor from 0.5 to 3 compared to its geometrical collection area, with a trend that roughly dependents on the electron temperature . In fact, the saturation current collected by the small pines has roughly a linear trend with the local plasma density, over at least a decade covering the usual SOL density regimes.…”

Section: -2mentioning

confidence: 97%

Electrostatic transport in L-mode scrape-off layer plasmas of Tore Supra tokamak. II. Transport by fluctuations

et al. 2012

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The turbulent transport of particles is investigated using rake probes at the top of the scrape-off layer (SOL) of circular ohmically heated L-mode plasmas in the Tore Supra tokamak [G. Giruzzi et al., Nucl. Fusion 49, 104010 (2009)]. Both radial and poloidal non-linear fluxes are estimated by means of two reciprocating arrays separated toroidally by 120. The time average of the radial (poloidal) flux is positive (negative) through the whole SOL profile. The respective effective transport velocity are about hv r i t % 30 m s À1 and hv h i t % À60 m s À1 close to the last closed flux surface. Both components present a standard deviation about 10 times higher than their respective mean amplitude, and time-distributions highly skewed toward values of the same sign as their mean values. The existence of a nonlinear poloidal flux is associated with the local tilt of filament eddies due to electric and magnetic shear. At the last closed flux surface, where plasma filaments experience their early life, the orientation of the velocity field is consistent with structure dynamics which originate from the outboard midplane and spread along field lines toward the rest of the poloidal section. The localized tilt of the eddy structures corresponds to the effect of the magnetic shear. Further into the SOL, the orientation of the velocity field evolves along radius in agreement with a simple model of propagating filaments progressively tilted by an electric shear. The combined effects of electric and magnetic shear on the eddy tilting have potentially a crucial impact on the existence of a Reynolds stress hv r v h i t component, which is strongly poloidally asymmetric at the edge of tokamak plasmas. V C 2012 American Institute of Physics. [http://dx

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Section: -2mentioning

confidence: 97%

Electrostatic transport in L-mode scrape-off layer plasmas of Tore Supra tokamak. II. Transport by fluctuations

et al. 2012

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“…Blob identification has been restricted to a portion of SOL profiles within 60 mm from the separatrix. When available, measurements with a second reciprocating probe, equipped with tunnel collectors, were used to infer electron temperature profiles. Otherwise, ad‐hoc temperature profiles were considered to be 30 eV at separatrix and an exponential radial decay length given by the decay length of the saturation current profile.…”

Section: Average Blobs From Tore Supramentioning

confidence: 99%

On the dynamics of blobs in scrape‐off layer plasma: Model validation from two‐dimensional simulations and experiments in Tore Supra

Fedorczak

Gallo

Tamain

et al. 2018

Contributions to Plasma Physics

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An investigation is proposed on the dynamics of blobs in scrape‐off layer (SOL) plasmas. Starting from a common reduced model predicting the dynamics of isolated blobs, we emphasize the necessity of verifying the meaningfulness of the notion of generic or average blob. A definition and methodology is proposed and tested on turbulent data built from two‐dimensional (2D) flux‐driven simulations. Average blobs are shown to possess physical properties in relatively good agreement with predictions made using the isolated blob model. An application to experimental data from Tore Supra is then demonstrated. A striking agreement is found between average blob velocities measured in experiments and isolated blob model predictions. It suggests that the turbulent transport in the SOL of limited plasmas is correctly described by 2D interchange models. A discussion is finally proposed that blob models have to focus on intermittency in order to find a field of application.

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“…In the frame of WEST, probes in the vicinity of the divertors will also be used for the determination of strike point position and particle flux intensity, and for plasma control, providing a real time feedback to control detachment. In Tore Supra, several types of probes are present: 2 vertical reciprocating probes settled in 2 upper ports [7], 2 magnetically driven probes mounted on an outer limiter [8], 4 arrays of fixed probes mounted in pumping slots under the limiter and 6 arrays of pop-up probes at the limiter surface. The first two types of probes will be maintained in WEST, whereas new probes will need to be integrated in the lower and upper divertors.…”

Section: Langmuir Probesmentioning

confidence: 99%

Diagnostic integration issues in the tore supra upgrade project WEST

Salasca

Bucalossi

Tsitrone

et al. 2013

2013 IEEE 25th Symposium on Fusion Engineering (SOFE)

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The WEST project (W -for tungsten -Environment in Steady-state Tokamak) consists in transforming the French tokamak Tore Supra into an X-point divertor one and aims at testing the ITER technology of actively cooled high heat flux tungsten components during ITER-relevant long pulses. In addition to the integration in the vacuum vessel of a lower divertor and an upper one, this metamorphosis has a strong impact on diagnostics initially present in Tore Supra. Indeed the introduction of a divertor in the upper part of the machine leads to block the lines of sight of diagnostics previously installed in the upper ports. Therefore new diagnostics playing a paramount role for the safe tokamak operation need to be implemented, such as an infrared thermography diagnostic for the protection of plasma-facing components (PFCs) and heating antennas, and a visible spectroscopy system for the protection of tungsten PFCs. Besides several existing diagnostics need to be modified to adapt their lines of sight to the new divertor targets and plasma shape. This paper presents the main issues linked to the integration of diagnostics deriving from the WEST upgrade project. First the changes involved by the upgrade on the set of diagnostics currently implemented in Tore Supra are described. Then a particular focus is put on the integration of the two new optical systems, namely the infrared system and the visible spectroscopy one. These two systems being located within the vacuum vessel, a special care must be paid to their design, to allow them to withstand their harsh environmental conditions. Other new or updated fundamental diagnostics are also briefly presented. Finally the resulting new implementation of diagnostics envisaged to reach the scientific and technological goals of the WEST project is described.

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Electric Probes in Tokamaks: Experience in Tore Supra

Cited by 22 publications

References 24 publications

Electrostatic transport in L-mode scrape-off layer plasmas of Tore Supra tokamak. II. Transport by fluctuations

Electrostatic transport in L-mode scrape-off layer plasmas of Tore Supra tokamak. II. Transport by fluctuations

On the dynamics of blobs in scrape‐off layer plasma: Model validation from two‐dimensional simulations and experiments in Tore Supra

Diagnostic integration issues in the tore supra upgrade project WEST

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