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The well-observed acoustic halo is an enhancement in time-averaged Dopplervelocity and intensity power with respect to quiet-sun values which isprominent for weak and highly inclined field around the penumbra of sunspotsand active regions. We perform 3D linear wave modelling with realisticdistributed acoustic sources in a MHS sunspot atmosphere and compare theresultant simulation enhancements with multi-height SDO observations of thephenomenon. We find that simulated halos are in good qualitative agreement withobservations. We also provide further proof that the underlying processresponsible for the halo is the refraction and return of fast magnetic waveswhich have undergone mode conversion at the critical $a=c$ atmospheric layer.In addition, we also find strong evidence that fast-Alfv\'en mode conversionplays a significant role in the structure of the halo, taking energy away fromphotospheric and chromospheric heights in the form of field-aligned Alfv\'enwaves. This conversion process may explain the observed "dual-ring" halostructure at higher ($> 8 $ mHz) frequencies.

3D simulations of realistic power halos in magneto-hydrostatic sunspot atmospheres: linking theory and observation