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Abstract

Observations of bright spots on the JET divertor aprons during lower hybrid current drive experiments are described. These bright spots are important because they can potentially cause damage to large tokamaks. The bright spots arise due to the impact of a fast particle beam. This beam originates from the front of the lower hybrid launcher, where thermal particles are accelerated according to theory by interaction with the high spatial harmonics of the lower hybrid wave. The bright spots are clearly related to the lower hybrid power as they disappear when the lower hybrid power is switched off. According to the analysis versus various parameters, the brightness of the spots clearly decreases with increasing plasma�wall distance, i.e. the distance between the last closed flux surface and the poloidal limiter. This is clearly beneficial for ITER, as it is designed to operate at a large plasma�wall distance.

Additional information

Authors: RANTAMÄKI K M, Association Euratom- Tekes, VTT Processes, VTT (FI);KARTTUNEN S J, Association Euratom- Tekes, VTT Processes, VTT (FI);PETRZILKA V, Association Euratom-IPP, Prague (CZ);FUCHS V, Association Euratom-IPP, Prague (CZ);ZACEK F, Association Euratom-IPP, Prague (CZ);ANDREW P, EURATOM-UKAEA Fusion Association, Culham Science Centre, Abingdon (GB);ERENTS K, EURATOM-UKAEA Fusion Association, Culham Science Centre, Abingdon (GB);LOMAS P, EURATOM-UKAEA Fusion Association, Culham Science Centre, Abingdon (GB);MAILLOUX J, EURATOM-UKAEA Fusion Association, Culham Science Centre, Abingdon (GB);MAYORAL M-L, EURATOM-UKAEA Fusion Association, Culham Science Centre, Abingdon (GB);MCDONALD D C, EURATOM-UKAEA Fusion Association, Culham Science Centre, Abingdon (GB);PARAIL V, EURATOM-UKAEA Fusion Association, Culham Science Centre, Abingdon (GB);COFFEY I, Queen�s University, Belfast (GB);EKEDAHL A, Département de Recherches sur la Fusion Contrôlée, Association Euratom-CEA sur la Fusion, CEA Cadarache, Saint-Paul-lez-Durance (FR);GONICHE M, Département de Recherches sur la Fusion Contrôlée, Association Euratom-CEA sur la Fusion, CEA Cadarache, Saint-Paul-lez-Durance (FR);JOFFRIN E, Département de Recherches sur la Fusion Contrôlée, Association Euratom-CEA sur la Fusion, CEA Cadarache, Saint-Paul-lez-Durance (FR);GRANUCCI G, Istituto di Fisica del Plasma, EURATOM�ENEA�CNR Association Milano (IT);MANTSINEN M, Association EURATOM-TEKES, Helsinki University of Technology (FI) Association EURATOM-TEKES, Helsinki University of Technology (FI);NOTERDAEME J-M, Max-Planck-Institut für Plasmaphysik, IPP-EURATOM Association, Garching (DE);TUCCILLO A A, Associazione Euratom-ENEA sulla Fusione, Centro.Richerche Energia ENEA-Frascati, Frascati (IT)
Bibliographic Reference: An article published in: Plasma Physics and Controlled Fusion 47 (2005) 1101�1108
Availability: This article can be accessed online by subscribers, and can be ordered online by non-subscribers, at: http://www.iop.org/EJ/journal/PPCF
Record Number: 200518312 / Last updated on: 2005-08-26
Category: PUBLICATION
Original language: en
Available languages: en