Axi-symmetrization of radiation pattern and two wave heating of fundamental ECRH in GAMMA 10

Citation
T. Saito et al., Axi-symmetrization of radiation pattern and two wave heating of fundamental ECRH in GAMMA 10, FUSION ENG, 53, 2001, pp. 267-275
Citations number
18
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Nuclear Emgineering
Journal title
FUSION ENGINEERING AND DESIGN
ISSN journal
0920-3796 → ACNP
Volume
53
Year of publication
2001
Pages
267 - 275
Database
ISI
SICI code
0920-3796(200101)53:<267:AORPAT>2.0.ZU;2-2
Abstract
In GAMMA 10, the radiation pattern of a heating wave of fundamental ECRH fo r potential formation was not axi-symmetric but vertically elongated on the resonance surface. The non-axisymmetric radiation pattern caused a non-axi symmetric potential profile and likely induced a radial loss. Then, the rad iation pattern has been axi-symmetrized. Accordingly, an almost axi-symmetr ic potential profile has been obtained and a large density increase during ECRH has been observed in the central cell. This implies that radial losses associated with ECRH have been substantially reduced. A new antenna has re cently been installed for additional plug electron heating (second ECRH). W ith this antenna, a larger power and/or a longer pulse width have become av ailable. In a most recent experiment, we have succeeded in axial plugging w ith a duration up to 0.15 s by sequential use of the usual ECRH and the sec ond ECRH. Moreover, there is an indication that the second ECRH is more des irable for further reduction of the radial loss. (C) 2001 Elsevier Science B.V. All rights reserved.