Improving the understanding of subsurface structure and dynamics of solar active regions

The goal of helioseismology is to provide accurate information about the Sun’s interior from the observations of the wave field at its surface. In the last three decades, both global and local helioseismology studies have made significant advances and breakthroughs in solar physics. However 3-d mapping of the structure and dynamics of sunspots and active regions below the surface has been a challenging task and are among the long standing and intriguing puzzles in solar physics due to the complexity of the turbulent and dynamic nature of magnetized regions. Thus the key problems that need to be addressed during the next decade are:  Understanding the wave excitation mechanisms in the quiet Sun and magnetic regions  Characterizing the wave propagation and transformation in strong and inclined magnetic field regions and understanding the magnetic portals in the chromosphere  Improving helioseismology techniques and investigating the whole life cycle of active regions, from magnetic flux emergence to dissipation  Detecting helioseismic signature of the magnetic flux of active regions before it becomes visible on the surface so as to provide warnings several days before the emergence For a transformative progress on these problems require  Full disk, simultaneous Doppler and vector magnetic field measurements of the photosphere up to the chromosphere with a spatial resolution of about 2 arc-sec  Large-scale radiative MHD simulations of the plasma dynamics from the subphotosphere to the chromosphere Multi-height observations will also able to estimate and correct the center-to-limb variation which is crucial for the measurement of meridional flow in the deeper convection zone including the tachocline region. These measurements will further help to reduce the convective background noise in the power spectra resulting in a more accurate determination of the oscillation frequencies.