Pellet fuelling into radiative improved confinement discharges in TEXTOR-94

Hobirk, J.; Messiaen, A.; Finken, K.H.; Ongena, J.; Brix, M.; Jaspers, R.; Koslowski, H. R.; Krämer–Flecken, A.; Mank, G.; Rapp, J.; Telesca, G.; Unterberg, B.

doi:10.1088/0029-5515/40/8/305

Cited by 7 publications

(4 citation statements)

References 24 publications

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“…The end of the enhanced confinement phase is triggered by the onset of a MARFE or by the increase in the neutral density at the edge in the case of multiple pellet injection. The most likely explanation is that the injected pellet does not create a new plasma mode of improved confinement but that it continues the RI mode to the upper limit, the density peaking allowing the stabilization of ITG modes deeper in the plasma core [213].…”

Section: Confinement and Transport Propertiesmentioning

confidence: 99%

Review: Pellet injection experiments and modelling

Pégouriè

2007

Plasma Phys. Control. Fusion

128

158

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During the last decade, significant progress has been made in the field of pellet injection with (1) the identification of the drift of the deposited material in the inhomogeneous magnetic field that opened the possibility of fuelling efficiently the plasmas from the high-field side of the torus, (2) the technique to mitigate ELMS in H-mode discharges with shallow pellet injection at high frequency and (3) with the development of high density, high performance scenarios close to the ITER requirements. Both the experimental and theoretical aspects of this domain are reviewed in this paper.

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Section: Confinement and Transport Propertiesmentioning

confidence: 99%

Review: Pellet injection experiments and modelling

Pégouriè

2007

Plasma Phys. Control. Fusion

128

158

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“…The dependence of confinement quality on the heating method is another important issue (Messiaen et al 1997). Processes leading to the termination of the RI-mode through the development of large-scale MHD-instabilities (Koslowski et al 1999) or the formation of MARFEs triggered at the inner edge by pellet injection (Hobirk et al 1999) have to be considered. An analysis of RI-core plasmas combined with an H-mode barrier at the edge of large devices as JET provides a great challenge for future work.…”

Section: Discussionmentioning

confidence: 99%

Hot Carrier Effects in p-Channel Polycrystalline Silicon Thin Film Transistors Fabricated on Flexible Substrates

Mariucci

Gaucci

Valletta

et al. 2007

jjap

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The characteristics of the toroidal ion temperature gradient (ITG) instability, considered as the main source of anomalous transport in the low (L) confinement mode of tokamaks, are analysed for the conditions of the radiatively improved (RI) mode triggered by seeding of impurities. Based on experimental profiles from TEXTOR-94 we deduce that the ITG-induced turbulence is quenched in the RI-mode in a large part of the plasma radius. Under those conditions the dissipative trapped electron (DTE) instability dominates the transport. The peaking of the electron density, one of the most remarkable features of the L-RI transition, is explained by the difference in contributions of ITG and DTE unstable modes to the diffusive and convective components of the electron flow. The shearing of the plasma toroidal velocity observed in the RI-modes with unbalanced neutral injection is successfully modelled by taking into account both the anomalous plasma viscosity due to ITG-turbulence and predictions of the revisited neoclassical theory. 0741-3335/99/SB0317+11$30.00

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“…Analysis of the effect of an ELM event on the radiation can give some valuable information about ELM mechanism. It was found that radiative cooling, which can give rise to improved confinement [13,14] or causes the formation of multifaceted asymmetric radiation from the edge (MARFE), [15] also plays an important role in triggering ELM events. The main impurities in the HL-2A are light impurities such as carbon and oxygen, and their profiles during H-mode, which are as long as profiles during L-mode, are shown in Fig.…”

Section: In Divertor Configurationmentioning

confidence: 99%

Properties of plasma radiation during discharges with improved confinement on HL-2A Tokamak

高金明¹,

刘仪²,

李伟³

et al. 2010

Chinese Phys. B

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In the recent experiment on the HL-2A tokamak, two types of improved confinement regimes have been achieved in different configurations. One is the improved confinement regime in limiter configuration during electron cyclotron resonant heating (ECRH), characterized by a sharp decrease in Hα emission accompanied by an increase in the total radiation of plasma, the line averaged electron density and the stored energy of plasma. The other is high confinement regime (H-mode) in divertor configuration during a combination of ECRH and Neutral beam injection (NBI) heating, characterized with edge localized modes (ELMs) besides the features mentioned above. The ELMs are found to be localized on the plasma edge (r/a ≥ 0.8), causing average losses of particles and stored energy in the ranges of about 1-3% and 3-5% respectively during a single ELM event. So far, the ELMs observed in the HL-2A are type III ELMs with low amplitude and high repetition frequency in a range from 200 Hz to 350 Hz. An investigation of the radiated power density profiles shows that radiative cooling effect plays a significant role in the transition back to the L-mode and the triggering of ELM events.

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Pellet fuelling into radiative improved confinement discharges in TEXTOR-94

Cited by 7 publications

References 24 publications

Review: Pellet injection experiments and modelling

Review: Pellet injection experiments and modelling

Hot Carrier Effects in p-Channel Polycrystalline Silicon Thin Film Transistors Fabricated on Flexible Substrates

Properties of plasma radiation during discharges with improved confinement on HL-2A Tokamak

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