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The diffusion of magnetic features with circular polarization, particularly in the internetwork (IN) area on the solar surface, demonstrates photospheric evolution. By studying them, one can reach to better understanding of complex dynamic of Sun such as solar magneto-convections. In this paper, we analyzed circular polarization features (hereafter CPFs) in the quiet Sun, using the high temporal and spatial resolution images of Stokes V from SUNRISE/IMaX magnetograms, to derive their characteristics and diffusive behaviors. The statistical and dynamical properties of CPFs are measured by an automatic feature tracking algorithm. Then, the displacement of CPFs are parameterized by diffusion index (γ) and diffusion coefficient (D). The CPFs are observed with average rate of occurrence of 1.7 × 10⁻²s⁻¹arcse⁻² and mean lifetime and area of 120s, 0.06Mm², respectively. Most of CPFs expand up to 1Mm². The CPFs migration represent a super diffusive motion with mean of γ = 1.44.

In recent years, there is a renewed debate about the origin of the observed prompt emission signal. Some authors found that synchrotron emission can dominate the spectra of several long bursts, and a recent analysis show that it may be possible to overcome the famous ‘line of death’ argument by a direct fitting procedure. On the other hand, several recent works showed that non-dissipative photosphere is preferred as the dominant emission model in at least 1/4 of long and 1/3 of short GRB population. Here I critically review the arguments given as well as their physical consequences. I present some recent results that show a connection between the prompt spectra and the early afterglow emission, thereby argue for an independent method of discriminating the physical conditions that result in the different dominant radiative processes.

A mature sunspot is usually surrounded by a penumbra: strong vertical magnetic field in the umbra, the dark central region of sunspot, becomes more and more horizontal toward the periphery forming an ensemble of a thin magnetic filaments of varying inclinations. Recent high resolution observations with the 1-meter Swedish Solar Telescope (SST) on La Palma revealed a fine substructure of penumbral filaments and new regularities in their dynamics.¹ These findings provide both the basis and constraints for an adequate model of the penumbra whose origin still remains enigmatic. We present results of recent observations obtained with the SST. Our data, taken simultaneously in 4305 Å G-band and 4396 Å continuum bandpasses and compiled in high cadence movies, confirm previous results and reveal new features of the penumbra. We find e.g. that individual filaments are cylindrical helices with a pitch/radius ratio providing their dynamic stability. We propose a mechanism that may explain the fine structure of penumbral filaments, the observed regularities, and their togetherness with sunspot formation. The mechanism is based on the anatomy of sunspots in which not only penumbra has a filamentary structure but umbra itself is a dense conglomerate of twisted interlaced flux tubes.