Sunspots suppress the local radiative flux by as much as 70–80%, posing a fundamental question of energy conservation: how is the blocked convective–radiative energy redistributed without compromising sunspot stability? Phase-correlation helioseismic holography of large sunspots in the 2.5–4.5 mHz band reveals signatures (Broock et al., 2023) consistent with fragmentation of magnetic flux into thin strands within the upper few hundred kilometers of the subphotosphere. Such structuring, long anticipated in Parker’s cluster model, provides a thermodynamically and magnetohydrodynamically plausible environment in which the inter-strand plasma may become overstable to vertical oscillations. These oscillations offer a natural pathway for converting blocked thermal energy into wave energy and I will discuss their properties.

Also, acoustic haloes surrounding sunspots exhibit enhanced high-frequency (≳5 mHz) acoustic emission, concentrated in peripheral regions of large sunspots.  While their observational signature is well established, their physical origin and energetic role remain unresolved. Halo formation likely reflects magnetoacoustic mode conversion and refraction in the β ≈ 1 layer, where the interplay between acoustic and magnetic restoring forces governs wave propagation. Elucidating these processes is crucial for understanding how magnetic structuring redistributes wave energy, modifies local energy densities, and potentially contributes to the dynamical stability and longevity of sunspots.