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Abstract

This contribution summarizes a number of aspects of the experimental and modelling programme at JET aimed at improving the characterization and understanding of edge localized mode (ELM) transport in the scrape-off layer (SOL). Divertor target energy deposition asymmetries favouring the inner target for the ion B x nabla B drift directed towards the X-point are observed with infra-red (IR) thermography. Similar trends are seen in the ELM resolved energy radiated in the divertor volume. Particle-in-cell kinetic calculations of the parallel ELM heat transport have been made for a range of ELM energies, revealing the detailed time response of target sheath heat transmission factors and indicating that electrons deposit ~30% of the ELM energy. The simulation results are in good agreement with experimental measurements of the integral energy deposited at the outer target up to the peak in target heat loads. A transient model of ELM filament energy evolution has been developed at JET and is able to reproduce a number of experimental observations, including the high ion energies observed in the far SOL using an electrostatic retarding field electrostatic analyser (RFA) and estimates of ELM heat fluxes deposited on main chamber limiters. During the ELM, the RFA and a second, SOL turbulence probe, clearly show the presence of coherent spikes in the hot ion flux, the plasma flux and the electron temperature. Field aligned structures have also been seen for the first time on JET in the power deposition on main wall limiters and upper dump plate surfaces using a new wide angle IR camera system. The probe signals are interpreted as the arrival of interspaced plasma filaments, with successive filaments carrying less energy. They are also consistent with the ELM out flux entering the SOL primarily on the outboard side and launching a sound wave disturbance along field lines.

Additional information

Authors: PITTS R A, Centre de Recherches en Physique des Plasmas, Association EURATOM-Confédération Suisse, Ecole Polytechnique Fédérale de Lausanne (CH);ANDREW P, EURATOM-UKAEA Fusion Association, Culham Science Centre, Abingdon (GB);FUNDAMENSKI W, EURATOM-UKAEA Fusion Association, Culham Science Centre, Abingdon (GB);ARNOUX G, Département de Recherches sur la Fusion Contrôlée, Association Euratom-CEA sur la Fusion, CEA Cadarache, Saint-Paul-lez-Durance (FR);EICH T, Max-Planck-Institut für Plasmaphysik, IPP-EURATOM Association, Garching (DE);HUBER A., Institut für Plasmaphysik, Forschungszentrum Jülich, Association EURATOM/FZJ, Trilateral Euregio Cluster, Jülich (DE);SILVA C, Associacao EURATOM-IST, Centro de Fusão Nuclear, Instituto Superior Técnico, Lisbon (PT);TSKHAKAYA D, Association EURATOM/ÖAW, Institute of Ion Physics and Applied Physics, University of Innsbruck, Innsbruck (AT)
Bibliographic Reference: An article published in: Nuclear Fusion 47 1437-1448 (2007)
Availability: This article can be accessed online by subscribers, and can be ordered online by non-subscribers, at: http://dx.doi.org/10.1088/0029-5515/47/11/005
Record Number: 200819683 / Last updated on: 2008-02-15
Category: PUBLICATION
Original language: en
Available languages: en