Measurement and simulation of edge plasma flow in the Tore Supra tokamak

Gunn, J.

doi:10.1007/bf03166392

Cited by 7 publications

(4 citation statements)

References 10 publications

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“…The same phenomenon is observed on JET [16]. Using a simple fluid modell it has been postulated that the observed flow is mainly due to a particle flux that is poloidally localized on the outboard side of the torus [17]. In order to verify this hypothesis special experiment has been performed when we moved plasma contact point poloidally on the outboard poloidal limiter APL during discharge.…”

Section: The Role Of Coherent Structures In Establishing the Width Ofsupporting

confidence: 50%

About bursty behaviour, coherent structures, wide scrape-off layer and large parallel flows in the edge of the Tore Supra tokamak

et al. 2006

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We present the measurements of plasma characteristics in the scrape-off layer (SOL) of the Tore Supra tokamak performed by means of reciprocating Langmuir probe. The probe is inserted into the machine from top. As the radial distance from last closed flux surface (LCFS) increases, ion saturation current exhibits stronger bursty character and its probability density function becomes increasingly skewed towards positive values. At the same time, burst duration and inter-burst time increase dramatically. We explain this phenomenon by radial propagation and dynamics of the ensemble of coherent turbulent structures of different size. The results of two-dimensional fluid modelling based of fluxdriven interchange instability mechanism are in excellent agreement with experimental results.We obtained clear experimental evidence that most of the coherent structures are formed in poloidally localized region of the SOL around the outboard midplane. If the probe is magnetically connected to this region, the SOL is very wide and we detect bursty behaviour in the far SOL. On the other hand, if the probe is not magnetically connected to the outboard midplane region (magnetic field lines are intercepted by the outboard limiter), then the SOL is very thin and bursty behaviour is much less prominent. Detection of bursty behaviour in the far SOL is correlated with existence of wide SOL pointing on important role of bursty transport by means of coherent turbulent structures in establishing the width of the SOL in tokamaks.The measurements of parallel flow in the SOL shows that plasma particle radial flux coming from confinement region to the SOL is mostly poloidally localized around the outboard midplane. Our estimations show that more than 80% of plasma particle radial flux is coming from confinement region to the SOL in poloidally localized region --approximately +15 ~ --around the outboard midplane.

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Section: The Role Of Coherent Structures In Establishing the Width Ofsupporting

confidence: 50%

About bursty behaviour, coherent structures, wide scrape-off layer and large parallel flows in the edge of the Tore Supra tokamak

et al. 2006

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“…Experimentally, such effects are important for turbulence spreading [75] and material interactions since even small drifts can compete with flows perpendicular to surfaces at the plasma-sheath interface [81] linear, as displayed in Table 5.2. The modified shearing rates on turbulent scales visualized in Figure 5…”

Section: The Experimental Calculationmentioning

confidence: 99%

Physics-informed machine learning techniques for edge plasma turbulence modelling in computational theory and experiment

Mathews¹

2022

Preprint

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“…The plasma parameters are usually different on the two sides of the probe. Parallel flows in the SOL [6,12] cause strong asymmetries of I sat ; the side of the probe that is nearer to the wall, or downstream of the SOL particle source, often measures a lower electron temperature [13]; the floating potential on the side that is connected to an outboard ICRH antenna often measures large positive floating potentials V f ∼150 V in a narrow layer around 1-2 cm thick [14], while simultaneously V f on the downstream side remains close to vacuum vessel ground. For this reason, the ion and electron side collectors are each biased with their own dedicated power supply.…”

Section: "Industrialization" Of Probe Measurements By Real-time Feedbmentioning

confidence: 99%

Electric Probes in Tokamaks: Experience in Tore Supra

Gunn

Pascal

Saint‐Laurent

et al. 2011

Contrib. Plasma Phys.

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Efforts to provide regular, automatic, and reliable reciprocating probe measurements in the scrape-off layer of the Tore Supra tokamak are described. Real time feedback on fast magnetic reconstruction is used to control the probe position relative to the last closed flux surface, while analysis of the current-voltage characteristics is used to adapt the voltage waveform applied to the probe, improving the dynamic range of the measurement. A large probe head is employed to ensure operation in the strongly magnetized plasma regime. Concave collectors embedded in the probe head, so-called "tunnel probes", are shown to be immune to sheath expansion effects, providing absolutely calibrated measurements of parallel ion current density.

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Measurement and simulation of edge plasma flow in the Tore Supra tokamak

Cited by 7 publications

References 10 publications

About bursty behaviour, coherent structures, wide scrape-off layer and large parallel flows in the edge of the Tore Supra tokamak

About bursty behaviour, coherent structures, wide scrape-off layer and large parallel flows in the edge of the Tore Supra tokamak

Physics-informed machine learning techniques for edge plasma turbulence modelling in computational theory and experiment

Electric Probes in Tokamaks: Experience in Tore Supra

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