I presented a talk entitled "Modeling the Origin of Tilt, Twist, Active Longitudes, and More: Buoyant Loops in Global Convective Dynamos", which was focused on the statistical properties of the ensemble of buoyant magnetic loops from my convective dynamo simulation (see papers here and here). One of the very interesting topics discussed at length concerns twist in sunspots. Previous simulations have indicated that buoyant magnetic loops need to be twisted in order to coherently rise through the solar convection zone. Measuring the twist in real sunspots is difficult and requires vector magnetograms which are only now becoming widely available, but observations seem to indicate that sunspots have an order of magnitude less twist on average than the minimum required by previous simulations. My simulated buoyant loops show a wide variety of amounts of twist and, on average, even slightly less than what is observed at the solar surface.
The histogram above shows the distribution of twists in my convective dynamo simulation (case S3) with a best-fit Gaussian distribution over-plotted in the black dashed curve. The vertical red dashed line shows the average twist observed in sunspots. Previous simulations have required a minimum twist rate on the order of +/-3 in these units. If the question is "Is twist required for the coherent rise of buoyant magnetic structures, or is it merely acquired from the dynamo generation mechanism?", the answer appears to be the latter.
It was a great conference and at a particularly beautiful location. The venue was Masion du Seminaires in Nice. As you can see from the pictures below, it was a spectacular venue.
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| View of Masion du Seminaires in Nice, France from the Mediterranean See. |
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| View of Nice and the Mediterranean See from a room like mine at the conference hotel. |
