Suppression of error-field-induced magnetic islands by Alfven resonance effect in rotating plasmas

Theory for error-field-induced magnetic islands is developed with inclusion of the Alfven resonance effect for rotating plasmas. The Alfven resonance effect changes the magnitude of tearing mode parameter (δ)' dramatically and makes (δ)' complex. This allows a new stationary state of non-rotating magnetic islands given by the balance between the convection term and (δ)' in the extended Rutherford equation. We found that the plasma rotation can reduce the island size compared to previous studies and even eliminate the islands completely when the error field is small. The Alfven resonance effect generates a significantly larger torque and makes the torque an increasing function of plasma rotation. This indicates the modification of the so-called forbidden band picture adopted to explain the low critical rotation frequency for resistive wall mode. (author)