Concept

Scolytinae

Publications associées (12)

Real-time control of ELM and sawtooth frequencies: similarities and differences

ELMs and Sawteeth, located in different parts of the plasma, are similar from a control engineering point of view. Both manifest themselves through quiescent periods interrupted by periodic collapses. For both, large collapses, following long quiescent per ...

IOP Publishing Ltd2016

ELM frequency feedback control on JET

Jonathan Graves

This paper describes the first development and implementation of a closed loop edge localized mode (ELM) frequency controller using gas injection as the actuator. The controller has been extensively used in recent experiments on JET and it has proved to wo ...

IOP Publishing Ltd2015

Snowmelt as a driver of ecosystem response in water limited mountain forests of the Western U.S.

Recent large-scale changes in snow cover over Western North America associated with climate warming may have widespread impacts on water availability. These changes have potentially varied impacts on water availability as snowmelt influences, soil moisture, streamflow, and evapotranspiration. These changes may significantly alter runoff production and gross primary productivity in mountain forests. Analysis of remotely sensed and in situ soil moisture data indicate strong sensitivities of the timing of peak

2015

Record-setting forest stress in the Rocky Mountains caused by low snowfall and high potential evapotranspiration, consistent with expected future conditions

Projections of future climate for the Southwestern U.S. and other semi-arid regions globally include reductions in mountain snow accumulation and increased summer potential evapotranspiration. These changes may significantly alter runoff production, evapotranspiration, and gross primary productivity in mountain forests. Analysis of remotely sensed vegetation greenness data indicate strong forest and understory growth dependencies associated with snow accumulation and snowmelt with peak snow water equivalent

2014

Edge-localized mode control by electron cyclotron waves in a tokamak plasma

Olivier Sauter, Stefano Coda, Timothy Goodman, Yves Martin, Jean-Marc Moret, Duccio Testa, Federico Alberto Alfredo Felici, Jonathan Rossel

Electron cyclotron resonance heating is applied to the edge of a high-confinement (H-mode) plasma featuring type I edge-localized modes (ELMs) in the TCV tokamak. As the deposition location is shifted gradually in a highly controlled manner towards the pla ...

IOP Publishing Ltd2012

ITER-relevant H-mode physics at ASDEX upgrade

Jonathan Bryan Lister, Yves Martin

A variety of techniques are being tested on ASDEX Upgrade for avoiding or reducing the divertor energy load caused by ELMs. Quiescent H-mode operation has been improved by operation with recently boronized vessel walls. Z(eff) values in QH-modes are now similar to2.5, comparable with those found in ELMy H-modes of similar density. Type It ELM operation has been generated in discharges with ICRF additional heating alone, thus demonstrating its compatibility with reactor-relevant low core momentum and particl

2004

Edge localized modes in DIII-D high performance discharges

Olivier Sauter

A new understanding of edge localized modes (ELMs) in tokamak discharges is emerging (Snyder P B et al 2002 Phys. Plasmas 9 2037), in which the ELM is an essentially ideal magnetohydrodynamic (MHD) instability and the ELM severity is determined by the radial width of the linearly unstable MHD kink modes. A detailed, comparative study of the penetration into the core of the respective linear instabilities in a standard DIII-D ELMing, high confinement mode (H-mode) discharge, with that for two relatively high

2003

ELM moderation with ICRF heating on JET

Olivier Sauter

A high-density, ELM-free, 'enhanced Dalpha' (EDA) H-mode has been demonstrated with Ohmic or RF heating on the Alcator C-Mod device. An allied 'low particle confinement' H-regime was also observed previously in 'Mk0' divertor experiments on JET. Initial attempts to recover similar states in the JET 'MkIIGB' divertor configuration are reported, employing appropriately shaped magnetic equilibria. Comparisons between cases with and without divertor cryopumping show enhanced edge sources tend to increase ELM fr

2002

Effects of type-I edge-localized modes on transport in ASDEX upgrade

Holger Reimerdes

Particle and energy losses due to type-I edge-localized modes (ELMs) and the effect of H-mode pedestal parameters on global confinement are studied for H-Mode discharges in ASDEX Upgrade. ELM frequency as well as particle and heat losses during ELMs are strongly affected by gas puffing, impurity injection, variation of plasma current and heating power. However the average power loss due to ELMs P-ELM = f(ELM)Delta W shows much less variation, and cannot account for the variations of stored energy encountere

1998

Effect on confinement of edge-localized modes in TCV

Henri Weisen, Richard Pitts, Yves Martin, Antoine Pochelon, Jean-Marc Moret

The effect of ELMs on confinement in ohmic H-modes has been investigated by analysing the rates of change of global parameters such as the electron content and the stored energy as a function of ELM frequency. In double-null H-modes, ELMs are found to expel on average 2% of the electron content and 2.5% of the stored energy. In single-null discharges which are separated by more than 2.2 cm from the inner wall, larger ELMs are observed which expel on average 3-7% of the electron content and 3-12% of the stor

1996

Ohmic H-modes in the TCV tokamak

Olivier Sauter, Basil Duval, Henri Weisen, Jonathan Bryan Lister, Richard Pitts, Yves Martin, Antoine Pochelon, Minh Quang Tran, Jean-Marc Moret, Roland Behn, Francis Troyon, Bernard Joye, René Chavan, Damien Fasel, Philippe Marmillod, Gilbert Tonetti, Xavier Llobet, Albert Perez, Blaise Marlétaz, Pierre Lavanchy, Pierre-François Isoz, Jean-Michel Mayor, Jean-Claude Magnin

The TCV tokamak has obtained ohmic H-modes in virtually all diverted plasmas with the ion del B drift directed towards an X-point and in several elongated limiter plasmas. Troyon factors (beta(tor)aB/l(p)) up to 2 and line average densities up to 2.2 x 10(20) m(-3), corresponding to the Greenwald limit, have been obtained in diverted ELM-free H-modes. Quasi-stationary H-modes lasting for the entire current flat top (1.5 s) have been obtained in the presence of regular ELMs. The occurrence and magnitude of E

1996

A Stereocontrolled Synthesis of the Pheromone 4-Methyl-3-heptanol : Novel and Selective CC-Linking Reactions

Manfred Schlosser

The Scolytus multistriatus aggregation pheromone (S,S)-4-methyl-3-heptanol was prepd. via 2 stereoselective steps. Reaction of (Z)-2-butenyl potassium with FB(OMe)2 at -75 Deg gave (Z)-MeCH:CHCH2B(OMe)2 which reacted with EtCHO to give >60% 96:4 erythro-4-methyl-5-hexene-3-ol (I) and threo-4-methyl-5-hexen-3-ol. Stereoselective homologation of I with AlMe3-TiCl4 and subsequent hydrolysis gave 32% II (RR = bond). This was hydrogenated to give quant. II (R = H). [on SciFinder (R)]

Wiley-VCH Verlag GmbH1982

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Publications associées (12)

Record-setting forest stress in the Rocky Mountains caused by low snowfall and high potential evapotranspiration, consistent with expected future conditions

2014