Related papers: Formation of Moving Magnetic Features and Penumbra…
Solar active regions show a wide variety of oscillatory phenomena. The presence of the magnetic field leads to the appearance of several wave modes, whose behavior is determined by the sunspot thermal and magnetic structure. We aim to study…
The sunspot penumbra comprises numerous thin, radially elongated filaments that are central for heat transport within the penumbra, but whose structure is still not clear. To investigate the fine-scale structure of these filaments, we…
Penumbrae are the manifestation of magnetoconvection in highly inclined (to the vertical direction) magnetic field. The penumbra of a sunspot tends to form, initially, along the arc of the umbra antipodal to the main region of flux…
Aims: We search for penumbral magnetic fields of opposite polarity and for their correspondence with downflows. Methods: We used spectropolarimetric HINODE data of a spot very close to disk center to suppress the horizontal velocity…
We study the presence of reversed polarity magnetic flux in sunspot penumbra. We applied a new regularized method to deconvolve spectropolarimetric data observed with the spectropolarimeter SP onboard Hinode. The new regularization is based…
We describe the characteristics and evolution of the magnetic field and chromospheric emission in an active region core observed by the Solar Optical Telescope on Hinode. Consistent with previous studies, we find that the moss is unipolar,…
The sunspot penumbra is a transition zone between the strong vertical magnetic field area (sunspot umbra) and the quiet Sun. The penumbra has a fine filamentary structure that is characterized by magnetic field lines inclined toward the…
A small decaying sunspot was observed with the Vacuum Tower Telescope (VTT) on Tenerife and the Japanese Hinode satellite. We obtained full Stokes scans in several wavelengths covering different heights in the solar atmosphere. Imaging time…
The photospheric Evershed flow is normally oriented radially outward, yet sometimes opposite velocities are observed not only in the chromosphere but also in the photospheric layers of the penumbra. We study the velocity field in a special…
We report the observations of the magneto-hydrodynamic waves propagating along magnetic flux tubes in the solar photosphere. We identified 20 isolated strong peaks (8 peaks for pores and 12 peaks for inter-granular magnetic structure) in…
The 3D structure of sunspots has been extensively studied for the last two decades. A recent advancement of the Stokes inversion technique prompts us to revisit the problem. We investigate the global depth-dependent thermal, velocity and…
We use spectro-polarimetric data recorded by Hinode to analyze the magnetic field configuration of a part of a sunspot (AR 10923) where a bundle of penumbral filaments are intruding into its umbra. We want to explore the role of the sunspot…
The Solar Optical Telescope onboard Hinode revealed the fine-scale structure of the Evershed flow and its relation to the filamentary structures of the sunspot penumbra. The Evershed flow is confined in narrow channels with nearly…
12 stable single sunspots were investigated in two aspects. The outer boundaries of the sunspots umbra were determined by an independent mathematical method and the vertical component of the magnetic field at these boundaries was found. We…
The flare-prolific active region NOAA 10930 offered both a developing delta-spot and a decaying satellite sunspot of opposite polarity. The objective of this study is to characterize the photometric decay of the satellite sunspot and the…
High-resolution time series of sunspots have been obtained with the Swedish 1m Solar Telescope between 2003 and 2006 at different locations on the solar disc. Proper motions in seven different active regions have been studied. The analysis…
A light bridge is a prominent structure commonly observed within a sunspot. Its presence usually triggers a wealth of dynamics in a sunspot, and has a lasting impact on sunspot evolution. However, the fundamental structure of light bridges…
A magnetic field is force-free if there is no interaction between the magnetic field and plasma in surrounding atmosphere i.e., electric currents are aligned with the magnetic field, giving rise to zero Lorentz force. Computation of various…
aims: We study the recently discovered twisting motion of bright penumbral filaments with the aim of constraining their geometry and the associated magnetic field. methods: A large sunspot located $40\degr$ from disk center was observed at…
Sunspot fine structure has been modeled in the past by a combination of idealized magneto-convection simulations and simplified models that prescribe the magnetic field and flow structure to a large degree. Advancement in numerical methods…