Questions for Dr. L Svalgaard ---- II Feb 22, 2013 20:41:46 GMT
Post by lsvalgaard on Feb 22, 2013 20:41:46 GMT
The L&P data is not analyzed separately for hemispheres. The raw data would allow this as the spot positions are known. You can find a discussion of Joy's law separated by hemispheres here arxiv.org/pdf/1209.1642.pdf
They find an asymmetry between the hemispheres in the mean tilt angles. On average, the tilts are greater in the southern than in the northern hemisphere for all latitude zones, and the differences increase with increasing latitude.
What do you think?
Yes, that was the paper I was reading. On a very little understanding of the physics, I would be inclined to think that magnetic field strength and rotation rate would determine the angle. That's why I was wondering if L&P ever produced separate hemisphere data.
As for "why"?? I could guess and say the radiative interior body that creates the shearing force is not always in the center of the sun and is pulled and distorted along the rotational axis much like a speaker magnet is pushed and pulled. When it reaches a certain height, shear generated flux is at minimum because the rotation is slower and upward momentum is stopped by gravity and reverses. It's also not a solid so it's more like a distortion in the distribution of volume that is cyclic. The volume distortion from an ideal cylinder would create different sunspots in N and S hemisphere including number and angle and field strength. the more complex the distortion, the stranger the effects might be. Just a thought.
I don't think the radiative interior is pulled anywhere. That is where almost all the mass is.