8 April 2013 to 3 May 2013
Nordita
Europe/Stockholm timezone

Mean-field theory of meridional flow and differential rotation

Not scheduled
132:028 (Nordita)

132:028

Nordita

Talk

Speaker

Leonid L. Kitchatinov (Institute for Solar-Terrestrial Physics, Irkutsk)

Description

Meridional circulation is driven by non-conservative parts of the centrifugal and buoyancy forces. Each of the forces alone would drive a flow of hundreds meters per second. The forces, however, almost balance each other in the so-called thermal wind balance. The meridional flow results from slight deviation from the balance. The flow attains its largest velocities in the boundary layers near the top and bottom of the convection zone, where the balance is violated, and decreases inside the convection zone. The differential rotation results from angular momentum transport by turbulent convection and by the meridional flow. Helioseismological rotation law can be reproduced only if the differential temperature is present with poles slightly warmer than the equator. Mean-field models predict the surface differential rotation of solar-type stars to be a function of only two stellar parameters: rotation period and surface temperature. The differential rotation is predicted to be smaller for smaller stars. Efficiency of the differential rotation in winding the toroidal fields has, however, an opposite tendency to increase with decreasing temperature.

Primary author

Leonid L. Kitchatinov (Institute for Solar-Terrestrial Physics, Irkutsk)

Presentation materials

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