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A new resonant cavity ICRF coupler is proposed for large tokamaks. The design features a novel resonant cavity, an RF magneticfield orientation that effectively radiates fast AlfvÃ©n waves, matching to 40-Â¿ transmission lines, and an electric-field orientation so that the strongest RF electric fields are orthogonal to the main toroidal magnetic field, thereby benefiting from magnetic insulation. As a result, the power handling capability is excellent. For the case of the "Big-Dee" Doublet III tokamak, a single 35 Ã 50-cm coupler can launch 20 mW of fast AlfvÃ©n waves. Extrapolation to fusion reactor parameters is straightforward.