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Bellizio T.,University of Naples Federico II | Albanese R.,University of Naples Federico II | Ambrosino G.,University of Naples Federico II | Ariola M.,University of Naples Federico II | And 15 more authors.
IEEE Transactions on Nuclear Science | Year: 2011

Tokamaks are the most promising approach for nuclear fusion on earth. They are toroidal machines where the plasma is heated in a ring-shaped vessel and kept away from the vessel by applied magnetic fields. To achieve high performance in tokamaks, plasmas with elongated poloidal cross-section are needed. Such elongated plasmas are vertically unstable, hence position control on a fast time scale is clearly an essential feature for all tokamak devices. In this context the Plasma Control Upgrade project was aimed at increasing the capabilities of the Vertical Stabilization (VS) of the JET tokamak. This paper introduces the new JET VS system and focuses on how the flexibility of this real-time system has been exploited to enlarge its operational limits in terms of maximum controllable disturbance. Eventually, some experimental results achieved during the last experimental campaigns are presented. © 2006 IEEE. Source

Romanelli F.,EFDA Close Support Unit | Laxaback M.,EURATOM
Green | Year: 2011

The achievement in the last two decades of controlled fusion in the laboratory environment is opening the way to the realization of fusion as a source of sustainable, safe and environmentally responsible energy. The next step towards this goal is the construction of the International Thermonuclear Experimental Reactor (ITER), which aims to demonstrate net fusion energy production on the reactor scale. This paper reviews the current status of magnetic confinement fusion research in view of the ITER project and provides an overview of the main remaining challenges on the way towards the realization of commercial fusion energy production in the second half of this century. Copyright © 2011 De Gruyter. Source

Bekris N.,EFDA Close Support Unit | Coad J.P.,Babcock Power | Grisolia C.,CEA Cadarache Center | Likonen J.,Tekes | And 3 more authors.
Journal of Nuclear Materials | Year: 2011

The JET Task Force Fusion Technology (TF-FT) has been launched with the aim of addressing issues related to JET and ITER. In this regard, studies related to the plasma-wall interactions identified erosion and deposition areas of the first wall of the vacuum vessel and provided the basis of our current knowledge on plasma-wall interaction processes at JET. In addition, characterisation of the properties of co-deposited layers covering the plasma exposed tiles have also been investigated and several detritiation techniques such as Laser Induced Breakdown Spectroscopy, or photon-cleaning have been successfully tested not only ex situ but also in situ. In the field of waste management, TF-FT also launched a series of tasks aiming at the detritiation of any kind of waste produced by a Fusion facility. Based on such studies it is now possible to scale up the developed detritiation facilities in order to be able to reach dimensions used at JET or ITER. © 2011 Elsevier B.V. All rights reserved. Source

Testa D.,Culham Center for Fusion Energy | Testa D.,Ecole Polytechnique Federale de Lausanne | Mellet N.,Culham Center for Fusion Energy | Mellet N.,Ecole Polytechnique Federale de Lausanne | And 9 more authors.
Nuclear Fusion | Year: 2010

This paper reports the first quantitative analysis of the measurements of the damping rate (γ/Ω) for stable Alfvén eigenmodes (AEs) with toroidal mode number (n) in the range |n| = 3-15 as a function of the edge plasma elongation (κ95). We find that the damping rate γ/ω versus κ95 for medium-n toroidal AEs (TAEs), with n = 3 and n = 7, increases for increasing elongation, i.e. its scaling versus κ95 follows the same trend previously measured and explained theoretically for the n = 1 and n = 2 TAEs. Theoretical analysis of the measurements for the n = 3 TAEs has been performed using the LEMan code. The results are in good agreement (within a factor of two) for all the magnetic configurations where there is only a very minor up/down asymmetry in the poloidal cross-section of the plasma. These experimental results further confirm the possibility of using the edge shape parameters as a real-time actuator for control of the stability of alpha-particle driven AEs in burning plasma experiments, such as ITER. © 2010 IAEA, Vienna. Source

Groth M.,Aalto University | Brezinsek S.,EURATOM | Belo P.,EURATOM | Corrigan G.,Culham Center for Fusion Energy | And 23 more authors.
Journal of Nuclear Materials | Year: 2013

Divertor radiation profiles, and power and particle fluxes to the target have been measured in attached JET L-mode plasmas with carbon and beryllium/tungsten wall materials. In the beryllium/tungsten configuration, factors of 2-3 higher power loads and peak temperatures at the low field side target were observed in high-recycling scrape-off layer conditions, whilst in close-to-sheath-limited conditions almost identical plasmas were obtained. The 30% reduction in total radiation with the beryllium/tungsten wall is consistent with a reduction of carbon as the dominant impurity radiator; however similar ion current to the plates, emission from recycling neutrals and neutral pressures in the pumping plenum were measured. Simulations with the EDGDE2/EIRENE code of these plasmas indicate a reduction of the total divertor radiation when carbon is omitted, but significantly higher power loads in high-recycling and detached conditions are predicted than measured. © 2013 Euratom. Published by Elsevier B.V. All rights reserved. Source

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