Observational results from active region seismology

Abstract

Active regions are one of the most observed features in the solar surface. High-resolution solar telescopes on ground and space have revealed the fine configuration of umbra and penumbra of sunspots with amazing detail. However, the subsurface structure of sunspots and active regions remains, for the most part, unknown. Thanks to the development of local helioseismology methods, the properties of active regions under the solar surface are starting to unravel. This paper reviews some of the main results obtained from the application of local helioseismology techniques to the study of the subsurface dynamics and magnetic properties of active regions.