Whitepaper #395 in the Decadal Survey for Solar and Space Physics (Heliophysics) 2024-2033. Main topics: basic research. Additional topics: ground-based missions/projects; solar physics.
Three-dimensional mapping of the structure and dynamics of sunspots and active regions below the photosphere are among the long standing and intriguing puzzles in solar physics. In order to make substantial progress in this field, we are advocating full disk, simultaneous Doppler and vector magnetic field observations at different heights of the solar atmosphere.