Search Publications
The study of umbral dots in sunspots based on SOT/Hinode observations
Ebadi, H.; Abbasvand, V.; Pourjavadi, H.
To understand the energy transport in sunspots, it is necessary to investigate the dynamic properties of umbral dots (UDs). In this connection, we used high-resolution SOT/Hinode time-series images. The intensity oscillations of UDs are determined. We conclude that their periods are in the range of 3-5 min, which may be related to the propagation …
Chromospheric activity in sunspot light bridges
Louis, R. E.
High-resolution filtergrams from Hinode were used to analyse the nature of chromospheric activity over a set of five sunspot light bridges. The broad-band Ca II H filtergrams depict a variety of phenomena which include large arc-shaped brightenings, bright patches, and small-scale jets. These strong brightenings are recurrent over a duration of se…
Multi-spectral observations of flares
Zuccarello, F.
Observations show that during solar flares radiation can be emitted across the entire electromagnetic spectrum, spanning from gamma rays to radio waves. These emissions, related to the conversion of magnetic energy into other forms of energy (kinetic, thermal, waves) through magnetic reconnection, are due to different physical processes that can o…
On the surface structure of sunspots
Franz, M.
A precise knowledge of the surface structure of sunspots is essential to construct adequate input models for helioseismic inversion tools. % and to gain information about the subsurface structure of sunspots. We summarize our recent findings about the velocity and magnetic field in and around sunspots using HINODE observation. To this end we quant…
Spectropolarimetric analysis of 3D MHD sunspot simulations
Solanki, S. K.; Borrero, J. M.; Rempel, M.
We have employed 3D non-grey MHD simulations of sunspots to compute theoretical Stokes profiles and compare the levels of circular and linear polarization in the simulations with those observed in a real sunspot. We find that the spatial distribution and average values of these quantities agree very well with the observations, although the polariz…
Center to limb variation of penumbral Stokes V profiles
Franz, M.; Schlichenmaier, R.
We investigated the horizontal and the vertical component of the Evershed flow (EF). To this end, we computed average Stokes V profiles for various velocity classes in penumbrae at different heliocentric angles. Our results show that for blueshifted profiles an additional lobe with the same polarity as the spot is present in the blue side of the a…
Review of Hinode results
Suematsu, Y.
Hinode is an observatory-style satellite, carrying three advanced instruments being designed and built to work together to explore the physical coupling between the photosphere and the upper layers for understanding the mechanism of dynamics and heating. The three instruments aboard are the Solar Optical Telescope (SOT), which can provide high-pre…
Probability distribution functions for the Sun's magnetic field
Stenflo, J. O.
Magnetoconvection structures the Sun's magnetic field cover a vast range of scales, down to the magnetic diffusion scale that is orders of magnitude smaller than the resolution of current telescopes. The statistical properties of this structuring are governed by probability density functions (PDFs) for the flux densities and by the angular distrib…