Sun's Dynamo

[harry]

G'day from the land of ozzzzzzzz

After talking to Chris about the Sun's cycles I got to thinking about the probable cycles within the Sun's Dynamo which incorporates the core of the Sun and its surroundings.

I assume in one way or another Stars have similar working parts.

So my next reading will be on the Sun's dynmo,,,,,,,,,,,,oops I see that some people are already running for the hills.

I have read a number of papers on the standard model of the Sun and find they fall short in explaining the workings of the Sun.

This following paper is quite interesting:

http://arxiv.org/abs/0906.4748
Outstanding Issues in Solar Dynamo Theory

Authors: Dibyendu Nandy
(Submitted on 25 Jun 2009)

Abstract: The magnetic activity of the Sun, as manifested in the sunspot cycle, originates deep within its convection zone through a dynamo mechanism which involves non-trivial interactions between the plasma and magnetic field in the solar interior. Recent advances in magnetohydrodynamic dynamo theory have led us closer towards a better understanding of the physics of the solar magnetic cycle. In conjunction, helioseismic observations of large-scale flows in the solar interior has now made it possible to constrain some of the parameters used in models of the solar cycle. In the first part of this review, I briefly describe this current state of understanding of the solar cycle. In the second part, I highlight some of the outstanding issues in solar dynamo theory related to the the nature of the dynamo $\alpha$-effect, magnetic buoyancy and the origin of Maunder-like minima in activity. I also discuss how poor constraints on key physical processes such as turbulent diffusion, meridional circulation and turbulent flux pumping confuse the relative roles of these vis-a-vis magnetic flux transport. I argue that unless some of these issues are addressed, no model of the solar cycle can claim to be ``the standard model'', nor can any predictions from such models be trusted; in other words, we are still not there yet.

[harry]

G'day

I wanted to post this in the other post.
It will take years before we get to understand the Sun, our nearest Star.


http://arxiv.org/abs/0907.4842
Why does the Sun's torsional oscillation begin before the sunspot cycle?

Authors: Sagar Chakraborty, Arnab Rai Choudhuri, Piyali Chatterjee
(Submitted on 28 Jul 2009)

Abstract: Although the Sun's torsional oscillation is believed to be driven by the Lorentz force associated with the sunspot cycle, this oscillation begins 2--3 yr before the sunspot cycle. We provide a theoretical explanation of this with the help of a solar dynamo model having a meridional circulation penetrating slightly below the bottom of the convection zone, because only in such dynamo models the strong toroidal field forms a few years before the sunspot cycle and at a higher latitude.