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Spatial maps of the high-pass frequency filtered time-averagedroot-mean-squared (RMS) Doppler velocities tend to show substantial decrementswithin regions of strong field and curiously, randomly distributed patches ofenhancement in the vicinity. We propose that these haloes or enhancements are aconsequence of magnetic-field-induced mode mixing (scattering), resulting inthe preferential powering of waves that possess strong surface velocitysignatures (i.e. scattering from low to high wavenumbers). Evidently, thisprocess can occur in the reverse, and therefore in order to determine if thehaloes are indeed caused by mode mixing, we must answer the question: {\it howare acoustic waves scattered by magnetic fields?} Through simulations of theinteractions between waves and sunspots and models of plage, we demonstratethat the high to low modal order scattering channels are favoured. Withincreasing frequency and consequently, decreasing wavelength, a growing numberof modes are scattered by the sunspot, thereby rendering the enhancements mostvisible around the high-frequency parts of the spectrum. The haloes obtainedfrom the simulations are on the same order of magnitude but weaker than thoseobserved. We also present observational evidence to support this theory:observations of active region AR9787 are firstly frequency filtered to isolatethe 5-6 mHz signals and secondly, decomposed into three wavenumber bandpasses,$l - [0,400], [400,800], [800,2222]$. With increasing wavenumber, the extent ofthe halo effect is seen increase dramatically, in line with theoreticalexpectation.

A Wave Scattering Theory of Solar Seismic Power Haloes