Sunspot Formation: Theory, Simulations and Observations

Session

Observational constraints and results from global helioseismology

Session2

9 Mar 2015, 11:10

Oskar Klein Auditorium (Albanova, Stockholm)

266. Flows in the Convection Zone with Potential Relevance to the Sunspot Problem.

Thomas Duvall (MPS Gottingen)

09/03/2015, 11:10

Recent results on convection zone flows will be examined, including the depth structure of supergranulation, the effect of the Coriolis force on supergranular flows, and upper limits on the amplitude of convection at different depths.

267. The radial gradient of the near-surface shear layer of the Sun

Atefeh Barekat (Max-Planck-Institut für Sonnensystemforschung (MPS))

09/03/2015, 11:50

Helioseismology has provided unprecedented information about the internal rotation of the Sun. One of the important achievements was the discovery of two radial shear layers: one near the bottom of the convection zone (the tachocline) and one near the surface. These shear layers may be important ingredients for explaining the magnetic cycle of the Sun. We measure the logarithmic radial...

265. Prediction of solar activity (Wolf numbers) based on nonlinear dynamo

Nathan Kleeorin (Ben-Gurion University of the Negev)

09/03/2015, 12:10

A one-dimensional nonlinear dynamo model (no R-model) is used for prediction of solar activity (Wolf numbers). The nonlinearity includes the dynamical equation for the magnetic helicity (the magnetic part of the alpha effect) and algebraic nonlinearity of the total alpha effect. The diffusion flux of magnetic helicity is taken into account. The Gnevyshev-Ohl rule works when only the...

264. Helicity observations as a constraint of dynamo models

Mei Zhang (National Astronomical Observatory of China)

09/03/2015, 12:40

We present our observations on current and kinetic helicities that provide constrains on solar dynamo models. We find that: (1) Current helicity in active regions present a clear hemispheric helicity sign rule but this rule also shows a solar-cycle variation. (2) Strong and weak magnetic fields show opposite helicity signs in active regions and this property may also has a solar-cycle...