Helioseismology

Abstract

Helioseismology is the study of solar interior using frequencies of solar oscillations. Frequencies of nearly half a million resonant modes of oscillations have been measured. Each of these mode is trapped in a different region of the solar interior and hence its frequency is sensitive to structure and dynamics in the corresponding region. Conversely, by combining the information from these large number of independent modes of solar oscillations it is possible to infer the structure and dynamics in most of the solar interior. These seismic data have provided a test for solar models and input physics like the equation of state, opacities and nuclear reaction rates. Some of the dynamical phenomenon inferred from these data are not yet understood. Some of these developments are described.