Maximizing absorption in ion-cyclotron heating of tokamak plasmas

Conference · Tue Apr 30 04:00:00 EDT 1991

OSTI ID:1178202

Bers, A. ^[1]; Fuchs, V. ^[2]; Chow, C. C. ^[3]

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1. Massachusetts Institute of Technology, Minneapolis, MN. Plasma Fusion Center; Massachusetts Institute of Technology, Minneapolis, MN. Plasma Fusion Center
2. Centre Canadien de Fusion Magnetique, Varennes, Quebec, Canada
3. Massachusetts Institute of Technology, Minneapolis, MN. Plasma Fusion Center

Efficient ion-cyclotron heating in tokamak plasmas is effectively localized in the central region of the plasma, near the ion second-harmonic layer in a single ion species plasma, or near the ion-ion hybrid layer in a plasma containing a minority ion species. The fast Alfven wave (FAW), which carries the incident rf power, from the low magnetic-field side, is generally focused in (by antenna design and propagation) toward this central region on the equatorial plane of the tokamak plasma. There the FAW encounters a "coupling" region and may undergo reflection (R), transmission(T)-to the high magnetic field side, mode conversion (C)-to an ion-Bernstein wave (IBW), and kinetic dissipation (D)-due to Doppler-shifted ion-cyclotron damping. (Here we ignore electron TTMP and/or Landau damping; these can be readily included by expanding on our formalism.) To determine these power transfer coefficients (R, T, C and D) the problem is in general formulated as an integro-partial-differential equation based upon the linearized Vlasov-Maxwell equations for an inhomogenous plasma. This is however difficult to solve, even numerically, and has been usually approximated by a fourth or sixth-order o.d.e. description which is amenable to numerical integration.

• Research Organization: Massachusetts Inst. of Tech., Cambridge, MA (US). Plasma Fusion Center
• Sponsoring Organization: USDOE; National Science Foundation
• DOE Contract Number: FG02-91ER54109
• OSTI ID: 1178202
• Report Number(s): PFC/JA-91-10; NSF Grant No. ECS-88-22475
• Country of Publication: United States
• Language: English