Helioseismology

Abstract

Many of the oscillations observed at the solar surface have been identified with resonant normal modes of the entire solar body. Accurate measurements of frequencies of these modes enable us to study the internal structure and dynamics of the Sun. Helioseismology has provided a handle to measure the depth of the convection zone and the primordial helium abundance, as well as the sound speed and the rotation velocity throughout much of thesolar interior.