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Related papers: I-mode pedestal relaxation events at ASDEX Upgrade

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In some conditions, I-mode plasmas can feature pedestal relaxation events (PREs) that transiently enhance the energy reaching the divertor target plates. To shed light into their appearance, characteristics and energy reaching the divertor…

The development of small- and no-ELM regimes for ITER is a high priority topic due to the risks associated to type-I ELMs. By considering non-linear extended MHD simulations of the ASDEX Upgrade tokamak with the JOREK code, we probe a…

An H-mode plasma state free of edge-localized mode (ELM), close to the L-H transition with clear density and temperature pedestal has been observed both at the Joint European Torus (JET) and at the ASDEX Upgrade (AUG) tokamaks usually…

Experimental measurements of plasma and neutral profiles across the pedestal are used in conjunction with 2D edge modeling to examine pedestal stiffness in Alcator C-Mod H-mode plasmas. Experiments on Alcator C-Mod observed pedestal…

Periodic edge localized modes (ELMs) are the non-linear consequences of pressure-gradient-driven ballooning modes and current-driven peeling modes becoming unstable in the pedestal region of high confinement fusion plasmas. In future…

Pedestal Relaxation Events (PREs) appear in I-mode discharges close to the I-H transition. Although they show certain similarities with Edge Localised Modes (ELMs), i.e. periodic energy ejections, the underlying mechanism seems to be very…

The theoretical investigation of relevant turbulent transport mechanisms in H-mode pedestals is a great scientific and numerical challenge. In this study, we address this challenge by global, nonlinear gyrokinetic simulations of a full…

Plasma Physics · Physics 2023-03-21 L. A. Leppin , T. Görler , M. Cavedon , M. G. Dunne , E. Wolfrum , F. Jenko , the ASDEX Upgrade Team

Power exhaust is one of the major challenges for a future fusion device. Applying a non-axisymmetric external magnetic perturbation is one technique that is studied in order to mitigate or suppress large edge localized modes which accompany…

BOUT++ turbulence simulations are conducted to capture the underlying physics of the small ELM characteristics achieved by increasing separatrix density via controlling strike points from vertical to horizontal divertor plates for three…

Plasma Physics · Physics 2022-12-14 Nami Li , X. Q. Xu , Y. F. Wang , X. Lin , N. Yan , G. S. Xu

By analyzing large quantities of discharges in the unfavorable ion $ \vec B\times \nabla B $ drift direction, the I-mode operation has been confirmed in EAST tokamak. During the L-mode to I-mode transition, the energy confinement has a…

Type-I Edge Localised Modes (ELMs) have been mitigated in MAST through the application of n = 3, 4 and 6 resonant magnetic perturbations (RMPs). For each toroidal mode number of the non-axisymmetric applied fields, the frequency of the ELMs…

A reproducible stationary improved confinement mode (I-mode) has been achieved recently in the Experimental Advanced Superconducting Tokamak, featuring good confinement without particle transport barrier, which could be beneficial to…

Naturally stable to ELMs, and with widths larger than EPED predictions, the I-modes are an excellent laboratory for investigating the role of drift micro-instabilities in pedestals since I-mode pedestal are not "limited" by MHD…

Plasma Physics · Physics 2020-05-19 Xing Liu , M. Kotschenreuther , D. R. Hatch , S. M. Mahajan , J. W. Hughes , A. E. Hubbard

Recent advances in the integrated modeling of ELMy H-mode plasmas are presented. A model for the H-mode pedestal and for the triggering of ELMs predicts the height, width, and shape of the H-mode pedestal and the frequency and width of…

I-mode is a natural ELMy-free regime with H-mode like improved energy confnement and L-mode like particle confnement, making it an attractive scenario for future tokamak based fusion reactors. A kind of low frequency oscillation was widely…

In future nuclear fusion reactors high heat load events, such as edge-localised modes (ELMs), can potentially damage divertor materials and release impurities into the main plasma, limiting plasma performance. The most difficult to handle…

Plasma Physics · Physics 2016-11-24 S. Elmore , S. Y. Allan , G. Fishpool , A. Kirk , A. J. Thornton , N. R. Walkden , J. R. Harrison

Alfven Eigenmodes are destabilized at the DIII-D pedestal during transient beta drops in high poloidal beta discharges with internal transport barriers (ITBs), driven by n=1 external kink modes, leading to energetic particle losses. There…

The density dependence of edge-localized-mode (ELM) suppression and density pump-out (density reduction) by n = 2 resonant magnetic perturbations (RMPs) is consistent with the effects of narrow well-separated magnetic islands at the top and…

Plasma Physics · Physics 2019-12-16 Q. M. Hu , R. Nazikian , B. Grierson , N. C. Logan , J-K. Park , C. Paz-Soldan , Q. Yu

Magnetically confined plasmas are often subject to relaxation oscillations accompanied by large transport events. This is particularly the case for the high confinement regime of tokamaks where these events are termed edge localized modes…

The type I ELMy H-mode is the baseline operating scenario for ITER. While it is known that the type I ELM ultimately results from the peeling-ballooning instability, there is growing experimental evidence that a mode grows up before the ELM…

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