Imaging of the Sun's Interior by Local Helioseismology
by
DrAlexander Kosovichev(W.W. Hansen Experimental Physics Laboratory, Stanford University)
→
Europe/Stockholm
Nordita Seminar Room
Nordita Seminar Room
Description
Local helioseismology techniques (time-distance helioseismology, acoustic imaging and holography, and ring-diagram analysis) use measurements of variations of acoustic travel times, phase shifts and local oscillation frequencies to infer the internal properties of the Sun. These techniques provide 3D maps of subsurface wave speed variations and flow velocities. The anisotropy of wave propagation in magnetic field is used to estimate properties of subsurface magnetic fields. The techniques are verified by using realistic numerical simulations of solar dynamics and wave propagation. The results reveal complicated dynamical structure of the solar interior. They provide new insight into large-scale convection and global circulation of the Sun, emergence and evolution of active regions, structure and dynamics sunspots and twisting and sheering flows in flaring regions.
