Observations of sunspots, active regions, filaments, coronal arcades, and interplanetary magnetic clouds indicate that the Sun preferentially exhibits left-handed, negative-helicity features in its northern hemisphere, and their opposite counterparts in the south, independent of sunspot cycle. We investigate quantitatively the generation of magnetic helicity by solar differential rotation actin...

There exists no signiÐcant correlation between the Homestake neutrino data up to run 133 and the monthly sunspot number, according to a test that is based on certain optimality properties for this type of problem. It is argued that priorly reported highly signiÐcant results for segments of the data are due to a statistical fallacy : the usual methods for evaluating the signiÐcance of common tes...

This paper offers the first coherent picture of the interactions between convection and magnetic fields that lead to the formation of the complicated filamentary structure of a sunspot penumbra. Recent observations have revealed the intricate interlocking-comb structure of the penumbral magnetic field. Some field lines, with associated Evershed outflows, plunge below the solar surface near the ...

We calculate helicities of solar active regions based on the idea that poloidal flux lines get wrapped around a toroidal flux tube rising through the convection zone, thereby giving rise to the helicity. Rough estimates based on this idea compare favorably with the observed magnitude of helicity. We use our solar dynamo model based on the Babcock-Leighton a-effect to study how helicity varies w...

The filamentary structure of a sunspot penumbra is believed to be magnetoconvective in origin. In the outer penumbra there is a difference in inclination of up to 30 Y40 between the magnetic fields associated with bright and dark filaments, and the latter fields plunge downward below the surface toward the edge of the spot.We have proposed that these fields are dragged downward bymagnetic pumpi...

Sunspots are Solar features located in active regions of the Sun, whose number is an indicator of the Sun’s magnetic activity. The Objective of this work is to study two automatic Sunspot detection algorithms such as Watershed transformation and K-means Clustering. In this paper, Sunspot is obtained by above stated methods from the full-disk solar images. This work presents a performance compar...

The receiver for the Small Radio Telescope (SRT) is being upgraded to a new, digital receiver to enable interferometry experiments. Part of our summer work was to test and debug this new receiver. Initial tests were done by observing the Sun using a short baseline of about 50 feet. During the recent high solar activity, the baseline was increased to about 200 feet. To compensate for the deviati...

Advances in instrumentation have made it possible to study sunspots with unprecedented detail. New capabilities include imaging observations at a resolution of 0. 1 (70 km on the sun), spectroscopy at ∼ 0. 2, and simultaneous spectropolarimetry in visible and infrared lines at resolutions well below 1. In spite of these advances, we still have not identified the building blocks of the penumbra ...

Arguments for and against the widely accepted picture of a solar dynamo being seated in the tachocline are reviewed, and alternative ideas concerning dynamos operating in the bulk of the convection zone, or perhaps even in the near-surface shear layer, are discussed. Based on the angular velocities of magnetic tracers, it is argued that the observations are compatible with a distributed dynamo ...