ocr: P-MODES, G-MODES, F-MODES Three kinds of waves are looked for in helioseismology: acoustic waves, for which pressure is the restoring force (these waves generate P modes), gravity waves for which buoyancy is the restoring force (these waves generate 9 modes), and surface gravity waves (these waves generate f modes. Both stand- ing wave patterns and propagating waves are used in research. The figure (leff) shows a diagram of ray paths of different acoustic (pres- sure) waves inside of the Sun. Pmodes (right) are oscil- lations of the whole Sun. The images show what happens when groups of oscill ...
