Abstract

Plasma flowing poleward at the solar surface and returning equatorward near the base of the convection zone, called the meridional circulation, constitutes the Sun's conveyor-belt. Just as the Earth's great oceanic conveyor-belt carries thermal signatures that determine El Nino events, the Sun's ... Show morePlasma flowing poleward at the solar surface and returning equatorward near the base of the convection zone, called the meridional circulation, constitutes the Sun's conveyor-belt. Just as the Earth's great oceanic conveyor-belt carries thermal signatures that determine El Nino events, the Sun's conveyor-belt determines timing, amplitude and shape of a solar cycle in flux-transport type dynamos. In cycle 23, the Sun's surface poleward meridional flow extended all the way to the pole, while in cycle 22 it switched to equatorward near 60°. Simulations from a flux-transport dynamo model including these observed differences in meridional circulation show that the transport of dynamo-generated magnetic flux via the longer conveyor-belt, with slower return-flow in cycle 23 compared to that in cycle 22, may have caused the longer duration of cycle 23. Show less