Extended Data Fig. 5: Overview of the data-driven model atmospheres used to synthesise MHD wave activity in a sunspot.

Stratified temperature models used as inputs for the Lare2D MHD code to synthesise the propagation and amplification of magnetoacoustic waves manifesting in the chromospheric resonant layers of a sunspot atmosphere. Note that the propagation distance corresponds to the physical distance covered by the propagating magnetoacoustic waves between a height of 0 km and the point when they experience a large temperature gradient (i.e., the commencement of the transition region; see the vertical dotted lines in Extended Data Fig. 4). For a vertically orientated magnetic field line, this also corresponds to the true geometric height of the upper chromosphere. However, if the magnetic field line that the magnetoacoustic waves propagate along is inclined to the solar normal (i.e., \(\cos \theta \ne 1\)), then this angle needs to be factored into the estimate of the true geometric height (see Equation 1 in the main text).