Spatial variations of the Sr i 4607 {\AA} scattering polarization peak

Context. The scattering polarization signal observed in the photospheric Sr i 4607 {\AA} line is expected to vary at granular spatial scales. This variation can be due to changes in the magnetic field intensity and orientation (Hanle effect), but also to spatial and temporal variations in the plasma properties. Measuring the spatial variation of such polarization signal would allow us to study the properties of the magnetic fields at subgranular scales, but observations are challenging since both high spatial resolution and high spectropolarimetric sensitivity are required. Aims. We aim to provide observational evidence of the polarization peak spatial variations, and to analyze the correlation they might have with granulation. Methods. Observations conjugating high spatial resolution and high spectropolarimetric precision were performed with the Zurich IMaging POLarimeter, ZIMPOL, at the GREGOR solar telescope, taking advantage of the adaptive optics system and the newly installed image derotator. Results. Spatial variations of the scattering polarization in the Sr i 4607 {\AA} line are clearly observed. The spatial scale of these variations is comparable with the granular size. Small correlations between the polarization signal amplitude and the continuum intensity indicate that the polarization is higher at the center of granules than in the intergranular lanes.Comment: 5 pages, 4 figure

Polarization of photospheric lines from turbulent dynamo simulations

We employ the magnetic and velocity fields from turbulent dynamo simulations to synthesize the polarization of a typical photospheric line. The synthetic Stokes profiles have properties in common with those observed in the quiet Sun. The simulated magnetograms present a level of signal similar to that of the Inter-Network regions. Asymmetric Stokes V profiles with two, three and more lobes appear in a natural way. The intensity profiles are broadened by the magnetic fields in fair agreement with observational limits. Furthermore, the Hanle depolarization signals of the Sr I 4607 A line turn out to be within the solar values. Differences between synthetic and observed polarized spectra can also be found. There is a shortage of Stokes V asymmetries, that we attribute to a deficit of structuring in the magnetic and velocity fields from the simulations as compared to the Sun This deficit may reflect the fact that the Reynolds numbers of the numerical data are still far from solar values. We consider the possibility that intense and tangled magnetic fields, like those in the simulations, exist in the Sun. This scenario has several important consequences. For example, less than 10% of the existing unsigned magnetic flux would be detected in present magnetograms. The existing flux would exceed by far that carried by active regions during the maximum of the solar cycle. Detecting these magnetic fields would involve improving the angular resolution, the techniques to interpret the polarization signals, and to a less extent, the polarimetric sensitivity.Comment: Accepted for publication in ApJ. 20 pag. 11 fig

Physics of Solar Prominences: II - Magnetic Structure and Dynamics

Observations and models of solar prominences are reviewed. We focus on non-eruptive prominences, and describe recent progress in four areas of prominence research: (1) magnetic structure deduced from observations and models, (2) the dynamics of prominence plasmas (formation and flows), (3) Magneto-hydrodynamic (MHD) waves in prominences and (4) the formation and large-scale patterns of the filament channels in which prominences are located. Finally, several outstanding issues in prominence research are discussed, along with observations and models required to resolve them.Comment: 75 pages, 31 pictures, review pape

The European Solar Telescope

The European Solar Telescope (EST) is a project aimed at studying the magnetic connectivity of the solar atmosphere, from the deep photosphere to the upper chromosphere. Its design combines the knowledge and expertise gathered by the European solar physics community during the construction and operation of state-of-the-art solar telescopes operating in visible and near-infrared wavelengths: the Swedish 1m Solar Telescope, the German Vacuum Tower Telescope and GREGOR, the French Télescope Héliographique pour l'Étude du Magnétisme et des Instabilités Solaires, and the Dutch Open Telescope. With its 4.2 m primary mirror and an open configuration, EST will become the most powerful European ground-based facility to study the Sun in the coming decades in the visible and near-infrared bands. EST uses the most innovative technological advances: the first adaptive secondary mirror ever used in a solar telescope, a complex multi-conjugate adaptive optics with deformable mirrors that form part of the optical design in a natural way, a polarimetrically compensated telescope design that eliminates the complex temporal variation and wavelength dependence of the telescope Mueller matrix, and an instrument suite containing several (etalon-based) tunable imaging spectropolarimeters and several integral field unit spectropolarimeters. This publication summarises some fundamental science questions that can be addressed with the telescope, together with a complete description of its major subsystems

The European Solar Telescope

The European Solar Telescope (EST) is a project aimed at studying the magnetic connectivity of the solar atmosphere, from the deep photosphere to the upper chromosphere. Its design combines the knowledge and expertise gathered by the European solar physics community during the construction and operation of state-of-the-art solar telescopes operating in visible and near-infrared wavelengths: the Swedish 1m Solar Telescope, the German Vacuum Tower Telescope and GREGOR, the French Télescope Héliographique pour l’Étude du Magnétisme et des Instabilités Solaires, and the Dutch Open Telescope. With its 4.2 m primary mirror and an open configuration, EST will become the most powerful European ground-based facility to study the Sun in the coming decades in the visible and near-infrared bands. EST uses the most innovative technological advances: the first adaptive secondary mirror ever used in a solar telescope, a complex multi-conjugate adaptive optics with deformable mirrors that form part of the optical design in a natural way, a polarimetrically compensated telescope design that eliminates the complex temporal variation and wavelength dependence of the telescope Mueller matrix, and an instrument suite containing several (etalon-based) tunable imaging spectropolarimeters and several integral field unit spectropolarimeters. This publication summarises some fundamental science questions that can be addressed with the telescope, together with a complete description of its major subsystems

Upaya Peningkatan Pengetahuan Masyarakat Tentang Pencegahan Stunting melalui Pendidikan Komunitas Interaktif

EFFORTS TO IMPROVE COMMUNITY KNOWLEDGE ABOUT STUNTING PREVENTION THROUGH EDUCATION OF INTERACTIVE COMMUNITIES. Stunting is one of the main health problems in Indonesia, including West Java Province. Some factors can cause this problem, especially inadequate nutrition. Community education regarding stunting prevention were delivered through interactive health promotion in Sayang village, Jatinangor sub-district, Sumedang district, West Java. The audiences were purposively selected, including village cadres and mothers with under-five children. The materials delivered in this program included practical information about how to prepare balanced nutrition for babies and under-five children. Seventy two audiences actively participated in this program. The enthusiasm of the audiences was very high, shown by very interactive discussion during this program. The participants could answer most of the questions given by the speakers. Community education through interactive health promotion which involved cadres and purposively selected group as the audiences was a reliable method to increase knowledge and awareness of the community for stunting prevention