The magnetic field and gravitational stratification creates inhomogeneous structures that have been observed across many scales in the solar atmosphere. These structures can guide the propagation of MHD waves and form the backbone of solar magneto-seismology and mechanisms such as resonant absorption, phase mixing, and mode coupling, which have been linked to coronal heating.
Solar magnetic waveguides are commonly cylindrical (flux tube) or slab-like in geometry. Just like waves along a guitar string, small amplitude MHD waves in solar waveguides are composed of a linear combination of eigenmodes. To aid understanding of MHD eigenmodes in inhomogeneous solar structures, click to see 3D animations of slab and flux tube eigenmodes.