Bidya Binay Karak, Arnab Rai Choudhuri
Guided by the recent observational result that the meridional circulation of
the Sun becomes weaker at the time of the sunspot maximum, we have included a
parametric quenching of the meridional circulation in solar dynamo models such
that the meridional circulation becomes weaker when the magnetic field at the
base of the convection zone is stronger. We find that a flux transport solar
dynamo tends to become unstable on including this quenching of meridional
circulation if the diffusivity in the convection zone is less than about $2
\times 10^{11}$ cm$^2$ s$^{-1}$. The quenching of $\alpha$, however, has a
stabilizing effect and it is possible to stabilize a dynamo with low
diffusivity with sufficiently strong $\alpha$-quenching. For dynamo models with
high diffusivity, the quenching of meridional circulation does not produce a
large effect and the dynamo remains stable. We present a solar-like solution
from a dynamo model with diffusivity $2.8 \times 10^{12}$ cm$^2$ s$^{-1}$ in
which the quenching of meridional circulation makes the meridional circulation
vary periodically with solar cycle as observed and does not have any other
significant effect on the dynamo.
View original:
http://arxiv.org/abs/1111.1540
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