Magnetic field modifies the properties of waves in a complex way. Significant advances has been made recently in our understanding of the physics of waves in solar active regions with the help of analytical theories, numerical simulations, as well as hi-resolution observations. In this contribution we review the current ideas in the field, with the emphasis on theoretical models of waves in sun...

Helioseismology observations from space missions SOHO and Hinode have provided tremendous amount of new information about thermodynamic properties and dynamics of plasma in the solar interior. The helioseismic diagnostics are based on measuring oscillation frequencies and travel times of acoustic waves excited by turbulent convection in subsurface layers. These diagnostics give us new insights ...

The relation between the Evershed flow and moving magnetic features (MMFs) is studied using highcadence, simultaneous spectropolarimetric measurements of a sunspot in visible (630.2 nm) and near-infrared (1565 nm) lines. Doppler velocities, magnetograms, and total linear polarization maps are calculated from the observed Stokes profiles. We follow the temporal evolution of two Evershed clouds t...

The total area coverage by starspots is of interest for a variety of reasons, but direct techniques only provide estimates of this important quantity. Sunspot areas exhibit a lognormal size distribution irrespective of the phase of the activity cycle, implying that most sunspots are small. Here we explore the consequences if starspot areas were similarly distributed. The solar data allow for an...

A hybrid system for the automated detection and McIntosh-based classification of sunspot groups on SOHO/MDI white-light images using active-region data extracted from SOHO/MDI magnetogram images is presented in this paper. After sunspots are detected from MDI white-light images they are grouped/clustered using MDI magnetogram images. By integrating image-processing and Neural Networks technique...