LONG-PERIOD EIGENOSCILLATIONS OF THE SOLAR INTERIOR: 1―3 YR, 20―40 YR, AND 1 500―20 000 YEAR MODES

摘要

Waves with periods much larger than the rotation period become trapped in the solar radiative interior. The modelling considers compressible, nonadiabatic, Rossby-like modes (ε-mechanism and radiative losses are taken into account) for a very small latitudinal gradient of rotation, without an arbitrary choice of other free parameters. We found global vorticity modes in 3 separate period ranges of ≈1―3 yr, 20―40 yr, and 1500―20 000yr which are maximum unstable. The discovered resonant cavity modes (called R-modes) are different from the known r-modes. We discuss some prospects to develop the theory of R-modes as a driver of the dynamics in the convective zone which could explain, e.g., observed short-term fluctuations of rotation, a control of the solar magnetic cycle, and abrupt changes of terrestrial climate in the past (Dansgaard-Oeschger events).