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Abstract

Generation of fast electrons in front of lower hybrid frequency (LHF) antennas is known to be caused by Landau damping of high N// components of the launched spectrum. These high N// components ([N//]>20) are expected to be absorbed within a very narrow layer (1-2mm) whereas infrared imaging of plasma facing components indicates a much broader (>5mm) heat flux deposition. Moreover this heat flux is found to depend on LHF electric field much more strongly than simulations predict.
A possible explanation of these discrepancies is the theoretically predicted enhancement of fast electron generation by spontaneously arising random fields. In this case a decrease of fluctuation level by absorption on fast electrons is expected along flux tubes connected to the antenna. For this hypothesis, two probes were installed on top of the LHF antenna. For further investigation of the fast electron flux, a retard field analyzer was reciprocated into the scrape-off layer during LHF power injection.

Additional information

Authors: GONICHE M (EDITOR), Departement de Recherches sur la Fusion Controlee, Association Euratom-CEA sur la Fusion, CEA Cadarache, Saint-Paul-lez-Durance (FR)
Bibliographic Reference: An oral paper given at: 31st EPS Conference on Controlled Fusion and Plasma Physics Organised by: CCLRC Rutherford Appleton Laboratory (GB); EURATOM/UKAEA Fusion Association (GB); Imperial College London Held at: Imperial College London (
Availability: Available from Association EURATOM-CEA, Departement de Recherches sur la Fusion Controlee, CEA Cadarache, F-13108 St Paul-Lez-Durance, France Tel: (+33) 4 42 25 70 01; Fax: (+33) 4 42 25 64 21 E-mail: dirdrfc@drfc.cad.cea.fr
Record Number: 200417624 / Last updated on: 2004-07-13
Category: PUBLICATION
Original language: en
Available languages: en