On the multiplicity of axisymmetric Alfvén continuous spectra in tokamaks

Axisymmetric Alfven continuous spectra are derived using the ideal MHD equations. The usual toroidal coupling effect due to the variation of the magnetic field strength is neglected, but the curvature coupling of the pressure fluctuation and the geodesic compressional effect are included. The cylindrical continuous spectrum of Alfven waves splits into two branches due to these effects. The frequency separation of the two m = 2 branches is much smaller than that of the two m = 1 branches. It is likely that the experimentally observed modes with smaller frequency separation are related to the two m = 1 continuum branches, while the modes with large frequency separation have different poloidal numbers.Axisymmetric Alfven continuous spectra are derived using the ideal MHD equations. The usual toroidal coupling effect due to the variation of the magnetic field strength is neglected, but the curvature coupling of the pressure fluctuation and the geodesic compressional effect are included. The cylindrical continuous spectrum of Alfven waves splits into two branches due to these effects. The frequency separation of the two m = 2 branches is much smaller than that of the two m = 1 branches. It is likely that the experimentally observed modes with smaller frequency separation are related to the two m = 1 continuum branches, while the modes with large frequency separation have different poloidal numbers.