Speaker
Mark Miesch
(High Altitude Observatory, National Center for Atmospheric Research, Boulder)
Description
The mean (axisymmetric) circulation in the meridional plane plays a key role in many
recent solar and stellar dynamo models. This is particularly the case in so-called
"Flux-Transport" dynamo models in which the meridional circulation regulates the
duration of magnetic activity cycles. Many of these models are kinematic in nature
so the meridional circulation must be prescribed. Yet, there is little guidance from
solar and stellar observations on what the subsurface circulation actually is. Here
we present constraints on the meridional circulation in the Sun and solar-like stars
obtained from global convection simulations as well as careful scrutinty of
helioseismic inversions within the context of the prevailing dynamical balances. We
find two dintinct mean flow regimes, delineated by the Rossby number. Fast rotators
exhibit multi-celled circulation
profiles and solar-like rotation profiles while slow rotators exhibit anti-solar
rotation profiles and single-cell (per hemisphere) circulation profiles. We identify
the dynamical processes responsible for these two regimes and we discuss the
implications with regard to mean flows and dynamo cycles in the Sun and stars.
Primary authors
Mark Miesch
(High Altitude Observatory, National Center for Atmospheric Research, Boulder)
Nicholas Featherstone
(High Altitude Observatory, National Center for Atmospheric Research, Boulder)
