and get mixed properties. In some setups, such as the axisymmetric waves in a straight cylinder with a circular basis (one of the simplest models for a coronal loop), the three MHD waves can still be clearly distinguished. But in general, the pure Alfvén and fast and slow magnetosonic waves don't exist, and the waves in the plasma are coupled to each other in intricate ways. See also Waves in plasmas Alfvén wave Ion acoustic wave Coronal seismology Magnetogravity wave References Waves in plasmas