RF-induced electric field and transport: experiments in non-fusion plasmas

Riccardi, C.; Bevilacqua, C.; Mozzi, D; Barni, R; Carrozza, R; Chiodini, G.; Fontanesi, M.; Hidalgo, C.

doi:10.1088/0741-3335/41/12b/315

Cited by 8 publications

(7 citation statements)

References 21 publications

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“…This implies a considerable modification of the global radial electric field in the SOL. A similar result was also observed in TFTR [6] and the Thorello device [7], where the radial electric field E r is strongly modified by the IBW in the vicinity of the resonant layer. The coherence between the two floating potentials is significantly reduced, as shown in Fig.…”

Section: Turbulence and Transport In Ibw Heated Plasmassupporting

confidence: 80%

“…Theory shows that IBWs, as well as fast waves, are the most promising methods to induce a poloidal flow [4,5]. This has been demonstrated experimentally in TFTR [6] and in non-fusion plasmas [7]. In the HT-7 tokamak, improved particle and energy confinement, as well as electron and ion heating, are achieved in the IBW heated plasmas by proper selection of the resonant location in the plasma [8].…”

Section: Introductionmentioning

confidence: 95%

“…Recently, IBW induced sheared poloidal flow has been observed at the location of the ion damping layer in TFTR [6]. Production of the Reynolds stress and radial electric field by the IBW has been demonstrated in Thorello, a non-fusion toroidal plasma device [7]. In the HT-7 tokamak, IBW heating is carried out successfully to heat the plasma [8].…”

Section: Turbulence and Transport In Ibw Heated Plasmasmentioning

confidence: 99%

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Turbulence and transport studies in the edge plasma of the HT-7 tokamak

et al. 2001

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The edge fluctuations and transport in the HT-7 tokamak are investigated using a Langmuir probe array in ohmic and IBW heated discharges. The normalized fluctuation levels are in the range 15-60% and 5-20% for electron density and temperature, respectively, and have the non-Boltzmann relation e Ṽf /Te > ñe/ne > Te/Te in the SOL of the ohmically heated plasmas. The fluctuation spectra show typical broadband features as observed in other tokamaks. In IBW heated plasmas, the particle confinement is greatly improved and the poloidal velocity shear in the SOL is strongly modified in a manner that is equivalent to an additional poloidal velocity in the electron diamagnetic direction produced by the IBW. A decorrelation in the fluctuations and the suppression of turbulent transport by the effect of the poloidal shear are found to be common mechanisms that are observed from the radial profiles of the fluctuating quantities in all these discharges. Electrostatically driven turbulent transport can account for a significant part of global particle losses in both ohmic and IBW heated plasmas.

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Section: Turbulence and Transport In Ibw Heated Plasmassupporting

confidence: 80%

Section: Introductionmentioning

confidence: 95%

Section: Turbulence and Transport In Ibw Heated Plasmasmentioning

confidence: 99%

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Turbulence and transport studies in the edge plasma of the HT-7 tokamak

et al. 2001

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“…In the early 1990s, it was suggested that turbulence suppression, leading to enhanced confinement regimes, could be accomplished using externally launched RF waves [216] to drive a localized sheared poloidal flow in the plasma. Over the past 15 years, a number of experiments have explored this possibility, with some success, using directly launched IBW waves [217][218][219][220][221]. The possibility of using the mode converted IBW to provide the sheared flow has been attempted on TFTR [222] and JET [221], with encouraging but inconclusive results.…”

Section: Plasma Control Applicationsmentioning

confidence: 99%

Chapter 6: Steady state operation

Gormezano¹,

et al. 2007

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Significant progress has been made in the area of advanced modes of operation that are candidates for achieving steady state conditions in a fusion reactor. The corresponding parameters, domain of operation, scenarios and integration issues of advanced scenarios are discussed in this chapter. A review of the presently developed scenarios, including discussions on operational space, is given. Significant progress has been made in the domain of heating and current drive in recent years, especially in the domain of off-axis current drive, which is essential for the achievement of the required current profile. The actuators for heating and current drive that are necessary to produce and control the advanced tokamak discharges are discussed, including modelling and predictions for ITER. The specific control issues for steady state operation are discussed, including the already existing experimental results as well as the various strategies and needs (qψ profile control and temperature gradients). Achievable parameters for the ITER steady state and hybrid scenarios with foreseen heating and current drive systems are discussed using modelling including actuators, allowing an assessment of achievable current profiles. Finally, a summary is given in the last section including outstanding issues and recommendations for further research and development.

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“…4,5 Sheared E ϫ B flows can influence the turbulence by shear decorrelation mechanisms and, as a consequence, modify the turbulent induced transport. 6 Recently a dynamical coupling between turbulent transport and parallel flows have been discovered in the edge of the Joint European Torus (JET) tokamak. 7 Results show that turbulent transport can drive substantial parallel flows in the plasma boundary of fusion plasmas.…”

Section: Introductionmentioning

confidence: 99%

Determination of velocity shears in a simple magnetized torus by means of a combined Langmuir and Mach probe

Riccardi

Barni

Fredriksen

2004

Review of Scientific Instruments

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We present a multiple electric probe setup for diagnostics of plasmas which is aimed to simultaneously measure the fluctuations of the ion velocity field along one direction and the ͑E ϫ B͒ flux perpendicular to it. The probe design is based on combining a Mach probe with two slightly spatially separated Langmuir probes. The probe has been prepared to operate in the turbulent regime of the simple magnetized torus Blaamann. Experiments have been focused on the measurements of shear in the velocity along the magnetic field and on its correlation with the radial flux. Preliminary results are showing the effectiveness of the proposed diagnostics as well as the relevance of velocity fluctuations and correlations in plasma turbulence and in anomalous transport.

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RF-induced electric field and transport: experiments in non-fusion plasmas

Cited by 8 publications

References 21 publications

Turbulence and transport studies in the edge plasma of the HT-7 tokamak

Turbulence and transport studies in the edge plasma of the HT-7 tokamak

Chapter 6: Steady state operation

Determination of velocity shears in a simple magnetized torus by means of a combined Langmuir and Mach probe

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