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Hu J.S.,CAS Hefei Institutes of Physical Science | Sun Z.,CAS Hefei Institutes of Physical Science | Li C.Z.,CAS Hefei Institutes of Physical Science | Zhen X.W.,CAS Hefei Institutes of Physical Science | And 16 more authors.
Journal of Nuclear Materials | Year: 2015

Abstract In this paper, we will present experimental results from EAST on the mitigation of edge localized modes (ELMs) using recently developed deuterium/lithium pellet injections as well as supersonic molecular beam injections (SMBI). Using a Laval nozzle, ELM mitigation with SMBI has been demonstrated in EAST in quasi-steady state. Using a D2 pellet injector, a giant ELM appears followed by a burst of high frequency ELMs at ∼300 Hz with duration of a few tens of milliseconds. Furthermore, for the first time, a novel technology using a simple rotating impeller to inject sub-millimeter size lithium (Li) granules at speeds of a few tens of meters per second was successfully used to pace ELMs. These experiments indicate that, on EAST, several technologies can contribute to the database supporting ELMs control in future fusion devices, such as ITER. © 2014 Elsevier B.V. Source


Plockl B.,Max Planck Institute for Plasma Physics (Garching) | Lang P.T.,Max Planck Institute for Plasma Physics (Garching) | Sellmair G.,Max Planck Institute for Plasma Physics (Garching) | Stober J.K.,Max Planck Institute for Plasma Physics (Garching) | And 2 more authors.
Fusion Engineering and Design | Year: 2013

After more than 20 years of operation and numerous modifications, a substantial modernisation of the inboard pellet injection system on ASDEX Upgrade was carried out. This enhancement was necessary to meet new functional requirements and to benefit from technical progress as well. New requirements are the integration in discharge control system, variation of settings of pellet train parameters during one discharge, temperature control of ice extrusion and overcome process limits caused by out-dated vacuum components. The programmable logic controller system is now fully migrated to S7-300 using High Speed Boolean Processor FM352-5 to replace hard-wired logic elements and enable flexible control of process parameters. First applications on ASDEX Upgrade concerning high density operation and ELM control are presented to confirm usefulness of implemented features. © 2013 Elsevier B.V. All rights reserved. Source


Vinyar I.,PELIN LLC. | Geraud A.,CEA Cadarache Center | Wyman M.,Tri Alpha Energy | Dequan L.,SWIP | And 4 more authors.
Fusion Engineering and Design | Year: 2011

Three innovative repetitive and multi-barrel deuterium ice pellet injectors have been designed for plasma investigations in fusion facilities. The pellet injector for JET can inject small pellets (variable volumes within 1-2 mm 3) at frequency up to 67 Hz and velocity 80-200 m/s for ELM (edge localised modes) control and large pellets (volume within 35-70 mm3) at frequency up to 15 Hz and velocity 100-300 m/s for plasma fueling. A new extrusion nozzle has been designed and tested to improve the extrusion stability and injection reliability. The pellet injector for HL-2A has a piston type extruder with a variable cross-section. It allows pushing out deuterium ice rod from the extruder at velocity up to 100 mm/s and injecting a limited number of pellets 1.3 mm diameter and variable length in the range 1.3-1.7 mm at frequency up to 30 Hz for plasma fueling. The pellet injector for fueling of a facility with theta pinch plasma is capable to inject one pellet with variable length from 5 to 15 mm and diameter 1 mm with extremely low velocity of about 40-50 m/s, followed by eleven pellets with variable length from 1 to 3 mm and diameter 0.9 mm at velocities 100-200 m/s. A novel gas valve with in-built punch mechanism has been developed to simplify the injector design. The design and distinct features of these three injectors are presented. © 2011 Elsevier B.V. All rights reserved. Source


Geraud A.,French Atomic Energy Commission | Lennholm M.,Culham Center for Fusion Energy | Alarcon T.,French Atomic Energy Commission | Bennett P.,Culham Center for Fusion Energy | And 6 more authors.
Fusion Engineering and Design | Year: 2013

A new high frequency pellet injector, part of the JET programme in support of ITER, has been installed on JET at the end of 2007. Its main objective is the mitigation of the Edge Localized Modes (ELMs), responsible for unacceptable thermal loads on the wall when their amplitude is too high. The injector was also required to have the capability to inject pellets for plasma fuelling. To reach this double goal, the injector has to be capable to produce and accelerate either small pellets to trigger ELMs (pace making), allowing to control their frequency and thus their amplitude, or large pellets to fuel the plasma. Operational since the beginning of the 2009 JET experimental campaign, the injector, based on the screw extruder technology, suffered from a general degradation of its performance linked to extrusion instability. After modifications of the nozzle assembly, re-commissioning on plasma has been undertaken during the first half of 2012 and successful pellet ELM pacing was achieved, rising the intrinsic ELM frequency up to 4.5 times. © 2013 EURATOM. Source


Xu H.B.,Southwestern Institute of Physics | Zhu G.L.,Southwestern Institute of Physics | Liu D.Q.,Southwestern Institute of Physics | Vinyar I.,PELIN LLC. | And 2 more authors.
Fusion Science and Technology | Year: 2012

A new pellet injector based on a piston-type extruder and a guide tube for magnetic high-field side (HFS) injection has been developed for HL-2A. Preliminary experimental results have been obtained by pellet injection. In this paper, the mechanisms of the pellet injector and the guide tube for HFS injection are described. Expert mental results of pellet edge-localized mode triggering and HFS pellet injection are also presented. Source

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