Solar internal rotation from helioseismology.

Observations of solar oscillations allow one to determine the properties of internal solar rotation. This branch of helioseismology, like most others, is enjoying rapid growth. Many diverse methods are used to determine the internal solar rotation. Measurements of p-mode frequencies made by several groups are in essential agreement that rotation within the convection zone differs in depth and latitude only slightly from the observed rotation of the surface. Deeper layers seem to rotate with less latitudinal differential rotation. The rotation of the energy-generating core is not well determined by p-mode oscillations and it may be rotating somewhat faster or at about the same rate as the surface. Observations of g-modes support the notion of a rapidly rotating core. Great improvements in knowledge of solar internal rotation are certain as higher resolution is obtained in images, frequency, and spherical harmonic degree and order. Signal-to-noise ratio will also improve greatly with the availability of continuous data from networks and from spacecraft.