Helioseismology: A probe of the solar interior, atmosphere, and activity cycle

Abstract

Helioseismology began in earnest in the mid-1970s. By 1977 helioseismology had demonstrated that the solar convection zone was about twice as deep as was previously thought to be the case. Since then helioseismology has also provided a measurement of the radial profile of the sound speed in the solar interior and it has also ruled out solar models which would attempt to solve the solar neutrino problem through a lowering of the temperature of the core, while at the same time showing that the effects of the diffusion of helium and other elements must be incorporated in the computation of the most accurate models of the solar interior. The field has also provided measurements of the radial and latitudinal profiles of the sun’s angular velocity over the outer half of the solar interior (as measured by radius). It has also provided evidence for helical flow patterns in the motions of the very shallow, sub-photospheric layers. Finally, the frequencies of the solar p-mode oscillations have also been demonstrate...