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 ...

High-cadence, multiwavelength optical observations of a solar active region (NOAA 10969), obtained with the Swedish Solar Telescope, are presented. Difference imaging of white light continuum data reveals a white light brightening, 2 min in duration, linked to a co-temporal and co-spatial C2.0 flare event. The flare kernel observed in the white light images has a diameter of 300 km, thus render...

A Bayesian probability based approach is applied to the problem of detecting and parameterizing oscillations in the upper solar atmosphere for the first time. Due to its statistical origin, this method provides a mechanism for determining the number of oscillations present, gives precise estimates of the oscillation parameters with a self-consistent statistical error analysis, and allows the os...

This analysis was conducted on 31 synoptic stations in Iran. Initially, the Mann-Kendall test was administered in order to analyse the trend of alterations of these two components over time and the results suggest that 16% of the stations show significant relationship with annual precipitation (positive and negative). More stations showed significant relationships between sunspots and minimum a...

Turbulent solar convection is a source of various processes observed as large-scale active phenomena, e.g., coronal mass ejections, formation of self-organized magnetic structures that appear on the surface as sunspots and pores, and other non-linear dynamical structures and phenomena. Modern realistic numerical simulations of solar turbulent phenomena are based on first physical principles and...

According to conventional view, sunspots form when coherent magnetic flux tubes intersect the surface. Such tubes would rise from the bottom of the convection zone as a result of an instability. In this study an alternative view is advanced where the field is produced throughout the entire convection zone and sunspots may form from local flux concentrations near the surface. In order to underst...

We present a comparative seismic study of conditions around and beneath isolated sunspots. Using the European Grid of Solar Observations’ Solar Feature Catalogue of sunspots derived from SOHO/MDI continuum and magnetogram data, 1996-2005, we identify a set of isolated sunspots by checking that within a Carrington Rotation there were no other spots detected in the vicinity. We then use level-2 t...