As recently found, the distribution of sunspots is non-axisymmetric and spot group formation implies the existence of two persistent active longitudes separated by 180◦. Here we quantitatively study the non-axisymmetry of sunspot occurrence. In a dynamic reference frame inferred from the differential rotation law, the raw sunspot data show a clear clustering around the persistent active longitu...

The fluting instability has been suggested as the driver of subsurface structure sunspot flux tubes. We conducted a series numerical experiments where we used tubes with different initial curvatures to study effect on spots. MURaM code, which previously simulate complete sunspots, first compute four sunspots in slab geometry and then two circular spots opposite polarities. find that curvature t...

We use daily observations from the Royal Greenwich Observatory and Kislovodsk Mountain Astronomical Station of Pulkovo to study distribution properties sunspot areas. To mitigate poor statistics in small areas, we introduce a "precision randomization" approach based on assumption that all measured areas have random component within measurement uncertainty 1 millionth solar hemisphere (M.S.H.). ...

This paper shows that an increase in corporate/labor/income tax rates may push an economy with tax evasion into an expansionary pattern, under increasing returns to scale. These effects would be reversed when the steady state is saddle-path stable. This model does not undertake a full identification. The interesting feature of our results is that fiscal policy in an economy with a significant u...