Evaluation of the capability of local helioseismology to discern between monolithic and spaghetti sunspot models

TL;DR

This study uses numerical simulations to compare helioseismic wave scattering in monolithic and spaghetti sunspot models, identifying measurable differences in absorption and phase shifts that can help distinguish sunspot structures.

Contribution

It demonstrates that helioseismic measurements can differentiate between monolithic and spaghetti sunspot models based on absorption and phase shift characteristics.

Findings

Spaghetti model shows steep increase in phase shift at short wavelengths.

Monolithic model exhibits more efficient mode-mixing.

Differences in absorption are detectable above noise level.

Abstract

The helioseismic properties of the wave scattering generated by monolithic and spaghetti sunspots are analyzed by means of numerical simulations. In these computations, an incident f or p1 mode travels through the sunspot model, which produces absorption and phase shift of the waves. The scattering is studied by inspecting the wavefield, computing travel-time shifts, and performing Fourier-Hankel analysis. The comparison between the results obtained for both sunspot models reveals that the differences in the absorption coefficient can be detected above noise level. The spaghetti model produces an steep increase of the phase shift with the degree of the mode at short wavelengths, while mode-mixing is more efficient for the monolithic model. These results provide a clue for what to look for in solar observations to discern the constitution of sunspots between the proposed monolithic and spaghetti models.