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Related papers: Microtearing Thresholds and Second-Stable Ballooni…

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Pedestal profiles that span the ELM cycle have been obtained and used to test the idea that the pedestal pressure gradient in MAST is limited by the onset of Kinetic Ballooning Modes (KBMs). During the inter-ELM period of a regularly type I…

Plasma Physics · Physics 2012-01-24 D. Dickinson , S. Saarelma , R. Scannell , A. Kirk , C. M. Roach , H. R. Wilson

The pedestal profile measurements in high triangularity JET plasmas show that with low fuelling the pedestal width decreases during the ELM cycle and with high fuelling it stays constant. In the low fuelling case the pedestal pressure…

Microtearing modes (MTMs) are unstable in the shallow gradient region just inside the top of the pedestal in the spherical tokamak experiment MAST, and may play an important role in the pedestal evolution. The linear properties of these…

Plasma Physics · Physics 2013-06-18 D. Dickinson , C. M. Roach , S. Saarelma , R. Scannell , A. Kirk , H. R. Wilson

Plasma equilibria reconstructed from the Mega-Amp Spherical Tokamak (MAST) have sufficient resolution to capture plasma evolution during the short period between edge-localized modes (ELMs). Immediately after the ELM steep gradients in…

Plasma Physics · Physics 2013-06-18 D. Dickinson , C. M. Roach , S. Saarelma , R. Scannell , A. Kirk , H. R. Wilson

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…

We report on a detailed study of magnetic fluctuations in the JET pedestal, employing basic theoretical considerations, gyrokinetic simulations, and experimental fluctuation data, to establish the physical basis for their origin, role, and…

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

Recently, theoretical analysis has identified plasma microinstabilities as the primary mechanism responsible for anomalous heat transport in tokamaks. In particular, the microtearing mode (MTM) has been credited with the production of…

Plasma Physics · Physics 2021-02-09 A. O. Nelson , F. M. Laggner , A. Diallo , Z. A. Xing , D. R. Smith , E. Kolemen

Global electromagnetic gyrokinetic simulations show the existence of near threshold conditions for both a high-$n$ kinetic ballooning mode (KBM) and an intermediate-$n$ kinetic version of peeling-ballooning mode (KPBM) in the edge pedestal…

Plasma Physics · Physics 2015-06-04 Weigang Wan , Scott E. Parker , Yang Chen , Zheng Yan , Richard J. Groebner , Philip B. Snyder

The EPED model [P.B. Snyder et al 2011 Nucl. Fusion 51 103016] had success describing the pedestals of the Type-I ELM and QH-mode operations in conventional tokamaks, by combining kinetic ballooning mode (KBM) and peeling-ballooning (PB)…

Plasma Physics · Physics 2026-04-28 M. S. Anastopoulos Tzanis , M. Yang , A. Kleiner , J. F. Parisi , G. M. Staebler , P. B. Snyder

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

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 peak pressure gradient in the pedestal (dPe/d{\psi}) on MAST varies little between edge localized modes (ELMs), although it varies between discharges due factors such as gas fuelling and plasma current. The pressure pedestal width in…

Plasma Physics · Physics 2014-02-28 R. Scannell , A. Kirk , I. T. Chapman

A gyrokinetic threshold model for pedestal width-height scaling prediction is applied to multiple devices and to a shaping and aspect-ratio scan giving $\Delta_{\mathrm{ped}} = 0.92 A^{1.04} \kappa^{-1.24} 0.38^{\delta}…

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…

This paper describes new modeling capabilities for predicting H-mode pedestal profiles in spherical tokamaks. Temperature profiles for NSTX discharges 132543 and 132588 are modeled by coupling the \textsc{astra} transport solver with…

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…

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…

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

Ballooning instabilities are widely believed to be a possible triggering mechanism for the onset of substorm and current disruption initiation in the near-Earth magnetotail. Yet the stability of the kinetic ballooning mode (KBM) in a global…

Space Physics · Physics 2019-01-01 Abdullah Khan , P. Zhu , A. Ali
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