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Recent experimental work on Tore-Supra has shown strong, central electron heating with ICRF power driving antennas at the low-field side (LFS) edge of the plasma. The conditions under which this strong electron heating was observed were threefold: the ion-cylcotron layers of the two-ion species plasma (H, 3HE) were near the plasma edge or outside the plasma; a mode-conversion/resonance layer was present inside the plasma, near its centre; a high-field-side (HFS) cutoff was present in the plasma. Under these conditions, the HFS cutoff, together with the resonance cutoff layer near mode conversion, forms an intrinsic plasma resonator (a resonant cavity) with coupling to the LFS. When coupling to this resonator is "critical", 100% of the LFS incident power is mode converted and damped (resonantly absorbed) on electrons. Kinetic theory analysis shows that the mode conversion of the LFS incident fast Alfvén wave (FAW) power is to an ion-Bernstein wave (IBW) which effectively (Landau) damps on electrons. This damping can occur in a short distance near mode conversion as the IBW propagates in a tokamak-confined plasma. More generally, and in relation to the antenna, there is an overall intrinsic resonantor coupled to the antenna, which contains the intrinsic resonator relative to the LFS incident FAW, and arises from the presence of an LFS cutoff near the antenna. The paper presents a one-dimensional analysis of two types of intrinsic plasma resonators containing a mode conversion layer at which resonant absorption/IBW Landau damping on electrons can occur for efficient electron heating and/or current drive in a tokamak plasma such as Tore Supra

Additional information

Authors: BERS A, Commissariat a l'Energie Atomique (FR)
Bibliographic Reference: Article: Theoretical analysis of an intrinsic plasma resonator coupled to an ICRF antenna - Tore Supra, 1998
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