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Abstract

Ion cyclotron resonance frequencies (ICRF) mode conversion has been developed for localized on-axis and off-axis bulk electron heating on the JET tokamak. The fast magnetosonic waves launched from the low-field side ICRF antennas are mode-converted to short-wavelength waves on the high-field side of the {3}He ion cyclotron resonance layer in D and {4}He plasmas and subsequently damped on the bulk electrons. The resulting electron power deposition, measured using ICRF power modulation, is narrow with a typical full-width at half-maximum of about 30 cm (i.e. about 30% of the minor radius) and the total deposited power to electrons comprises at least up to 80% of the applied ICRF power. The ICRF mode conversion power deposition has been kept constant using {3}He bleed throughout the ICRF phase with a typical duration of 4-6 s, i.e. 15-40 energy confinement times. Using waves propagating in the counter-current direction minimizes competing ion damping in the presence of co-injected deuterium beam ions.

Additional information

Authors: MANTSINEN M J (Editor), Helsinki University of Technology, Association Euratom�Tekes, Finland
Bibliographic Reference: An article published in: Nucl. Fusion 44 (2004) 33�46 PII: S0029-5515(04)70810-8
Availability: This article can be accessed online by subscribers, and can be ordered online by non-subscribers, at: stacks.iop.org/NF/44/33
Record Number: 200417451 / Last updated on: 2004-03-26
Category: PUBLICATION
Original language: en
Available languages: en