Whitepaper #449 in the Decadal Survey for Solar and Space Physics (Heliophysics) 2024-2033. Main topics: space weather applications; basic research. Additional topics: space weather research/operations/research loop; solar physics; space-based missions/projects; […]
Almost all helioseismology was done using observations along the Sun-Earth line. But the limited field of view limits our capability to investigating the deeper interior of the Sun or the dynamical processes beneath sunspots. One or more missions in the ecliptic plane, with larger separation angles relative to the Sun-Earth line, will help us advance our understanding of the solar interior.