Author name code: murabito ADS astronomy entries on 2022-09-14 author:Murabito, Mariarita ------------------------------------------------------------------------ Title: Investigating of the nature of magnetic oscillations associated with FIP effect Authors: Murabito, Mariarita; Jafarzadeh, Shahin; Van Driel-Gesztelyi, Lidia; Ermolli, Ilaria; Baker, Deborah; Brooks, David; Long, David; Jess, David; Valori, Gherardo; Stangalini, Marco Bibcode: 2022cosp...44.2591M Altcode: Observations of the photosphere, chromosphere, and corona combined with magnetic field modeling of one of the biggest sunspots of the 24 solar cycle, revealed that regions of high FIP bias plasma in the corona were magnetically linked to the locations of the intrinsic magnetic oscillations in the solar chromosphere. In order to characterize the driver of the oscillations, we analyzed the relation between the spatial distribution of the magnetic wave power and the overall field geometry and plasma parameters obtained from the multi-height spectropolarimetric non-local thermodynamic equilibrium (NLTE) inversions. In correspondence with the locations where the magnetic wave energy is observed at chromospheric heights, we found evidence in support of locally excited acoustic waves that, after crossing the equipartition layer located close to the umbra-penumbra boundary at photospheric heights, are converted into magnetic-like waves. These results indicate a direct connection between sunspot chromospheric activity and observable changes in coronal plasma composition, demonstrating the power of high resolution, multi-height studies of the solar atmosphere that will become the gold standard in the era of DKIST. Title: The umbral filament of active region NOAA 12529 Authors: Guglielmino, Salvatore Luigi; Romano, Paolo; Zuccarello, Francesca; Murabito, Mariarita; Ruiz Cobo, Basilio Bibcode: 2022cosp...44.2453G Altcode: Umbral filaments are elongated, filamentary bright structures inside sunspot umbrae, which differ in morphology, magnetic configuration, and evolution from light bridges usually observed in sunspots. We investigated an umbral filament (UF) observed in the umbra of the giant leading sunspot of active region NOAA 12529, analyzing high-resolution observations taken in the photosphere with the spectropolarimeter aboard the \textit{Hinode} satellite and in the upper chromosphere and transition region with the \textit{IRIS} telescope. We recognize in the UF the presence of a strong horizontal field larger than 2500 G, a significant portion of the UF with opposite polarity with respect to the surroundings, and filaments in the upper atmospheric layers corresponding to the UF in the photosphere. These findings suggest that this UF is the photospheric manifestation of a flux rope hanging above the sunspot and forming penumbral-like filaments within the umbra via magneto-convection. Title: The identification of magnetic perturbations in the solar atmosphere Authors: Stangalini, Marco; Jafarzadeh, Shahin; Baker, Deborah; Jess, David; Murabito, Mariarita; Valori, Gherardo Bibcode: 2022cosp...44.2590S Altcode: Magneto-hydrodynamic (MHD) waves and, in particular, magnetic perturbations associated with specific wave modes are thought to be important mechanisms not only for the heating of the outer layers of the Sun's atmosphere, but also for the elemental abundance anomaly observed in the corona. High resolution spectropolarimetry is nowadays progressively extending to the upper layers of the solar atmosphere, and this provides invaluable insight into MHD wave processes up to chromospheric heights. However, the identification of real magnetic perturbations remains a difficult task due to a number of spurious effects that can mimic the signals associated with them. In this contribution we will show a novel approach to the identification of real magnetic oscillations potentially linked to FIP and discuss proxies to be used in statistical analyses. Title: IBIS-A: The IBIS data Archive. High-resolution observations of the solar photosphere and chromosphere with contextual data Authors: Ermolli, Ilaria; Giorgi, Fabrizio; Murabito, Mariarita; Stangalini, Marco; Guido, Vincenzo; Molinaro, Marco; Romano, Paolo; Guglielmino, Salvatore L.; Viavattene, Giorgio; Cauzzi, Gianna; Criscuoli, Serena; Reardon, Kevin P.; Tritschler, Alexandra Bibcode: 2022A&A...661A..74E Altcode: 2022arXiv220209946E Context. The IBIS data Archive (IBIS-A) stores data acquired with the Interferometric BIdimensional Spectropolarimeter (IBIS), which was operated at the Dunn Solar Telescope of the US National Solar Observatory from June 2003 to June 2019. The instrument provided series of high-resolution narrowband spectropolarimetric imaging observations of the photosphere and chromosphere in the range 5800-8600 Å and co-temporal broadband observations in the same spectral range and with the same field of view as for the polarimetric data.
Aims: We present the data currently stored in IBIS-A, as well as the interface utilized to explore such data and facilitate its scientific exploitation. To this end, we also describe the use of IBIS-A data in recent and undergoing studies relevant to solar physics and space weather research.
Methods: IBIS-A includes raw and calibrated observations, as well as science-ready data. The latter comprise maps of the circular, linear, and net circular polarization, and of the magnetic and velocity fields derived for a significant fraction of the series available in the archive. IBIS-A furthermore contains links to observations complementary to the IBIS data, such as co-temporal high-resolution observations of the solar atmosphere available from the instruments onboard the Hinode and IRIS satellites, and full-disk multi-band images from INAF solar telescopes.
Results: IBIS-A currently consists of 30 TB of data taken with IBIS during 28 observing campaigns performed in 2008 and from 2012 to 2019 on 159 days. Of the observations, 29% are released as Level 1 data calibrated for instrumental response and compensated for residual seeing degradation, while 10% of the calibrated data are also available as Level 1.5 format as multi-dimensional arrays of circular, linear, and net circular polarization maps, and line-of-sight velocity patterns; 81% of the photospheric calibrated series present Level 2 data with the view of the magnetic and velocity fields of the targets, as derived from data inversion with the Very Fast Inversion of the Stokes Vector code. Metadata and movies of each calibrated and science-ready series are also available to help users evaluate observing conditions.
Conclusions: IBIS-A represents a unique resource for investigating the plasma processes in the solar atmosphere and the solar origin of space weather events. The archive currently contains 454 different series of observations. A recently undertaken effort to preserve IBIS observations is expected to lead in the future to an increase in the raw measurements and the fraction of processed data available in IBIS-A.

Research supported by the H2020 SOLARNET grant no. 824135. Title: The Importance of Horizontal Poynting Flux in the Solar Photosphere Authors: Silva, Suzana S. A.; Murabito, Mariarita; Jafarzadeh, Shahin; Stangalini, Marco; Verth, Gary; Ballai, Istvan; Fedun, Viktor Bibcode: 2022ApJ...927..146S Altcode: 2022arXiv220301221S The electromagnetic energy flux in the lower atmosphere of the Sun is a key tool to describe the energy balance of the solar atmosphere. Current investigations on energy flux in the solar atmosphere focus primarily on the vertical electromagnetic flux through the photosphere, ignoring the Poynting flux in other directions and its possible contributions to local heating. Based on a realistic Bifrost simulation of a quiet-Sun (coronal hole) atmosphere, we find that the total electromagnetic energy flux in the photosphere occurs mainly parallel to the photosphere, concentrating in small regions along intergranular lanes. Thereby, it was possible to define a proxy for this energy flux based on only variables that can be promptly retrieved from observations, namely, horizontal velocities of the small-scale magnetic elements and their longitudinal magnetic flux. Our proxy accurately describes the actual Poynting flux distribution in the simulations, with the electromagnetic energy flux reaching 1010 erg cm-2 s-1. To validate our findings, we extended the analysis to SUNRISE/IMaX data. First, we show that Bifrost realistically describes photospheric quiet-Sun regions, as the simulation presents similar distributions for line-of-sight magnetic flux and horizontal velocity field. Second, we found very similar horizontal Poynting flux proxy distributions for the simulated photosphere and observational data. Our results also indicate that the horizontal Poynting flux in the observations is considerably larger than the vertical electromagnetic flux from previous observational estimates. Therefore, our analysis confirms that the electromagnetic energy flux in the photosphere is mainly horizontal and is most intense in localized regions along intergranular lanes. Title: Large scale coherent magnetohydrodynamic oscillations in a sunspot Authors: Stangalini, M.; Verth, G.; Fedun, V.; Aldhafeeri, A. A.; Jess, D. B.; Jafarzadeh, S.; Keys, P. H.; Fleck, B.; Terradas, J.; Murabito, M.; Ermolli, I.; Soler, R.; Giorgi, F.; MacBride, C. D. Bibcode: 2022NatCo..13..479S Altcode: Although theoretically predicted, the simultaneous excitation of several resonant modes in sunspots has not been observed. Like any harmonic oscillator, a solar magnetic flux tube can support a variety of resonances, which constitute the natural response of the system to external forcing. Apart from a few single low order eigenmodes in small scale magnetic structures, several simultaneous resonant modes were not found in extremely large sunspots. Here we report the detection of the largest-scale coherent oscillations observed in a sunspot, with a spectrum significantly different from the Sun's global acoustic oscillations, incorporating a superposition of many resonant wave modes. Magnetohydrodynamic numerical modeling agrees with the observations. Our findings not only demonstrate the possible excitation of coherent oscillations over spatial scales as large as 30-40 Mm in extreme magnetic flux regions in the solar atmosphere, but also paves the way for their diagnostic applications in other astrophysical contexts. Title: Investigating the origin of magnetic perturbations associated with the FIP Effect Authors: Murabito, M.; Stangalini, M.; Baker, D.; Valori, G.; Jess, D. B.; Jafarzadeh, S.; Brooks, D. H.; Ermolli, I.; Giorgi, F.; Grant, S. D. T.; Long, D. M.; van Driel-Gesztelyi, L. Bibcode: 2021A&A...656A..87M Altcode: 2021arXiv210811164M Recently, magnetic oscillations were detected in the chromosphere of a large sunspot and found to be linked to the coronal locations where a first ionization potential (FIP) effect was observed. In an attempt to shed light on the possible excitation mechanisms of these localized waves, we further investigate the same data by focusing on the relation between the spatial distribution of the magnetic wave power and the overall field geometry and plasma parameters obtained from multi-height spectropolarimetric non-local thermodynamic equilibrium (NLTE) inversions of IBIS data. We find, in correspondence with the locations where the magnetic wave energy is observed at chromospheric heights, that the magnetic fields have smaller scale heights, meaning faster expansions of the field lines, which ultimately results in stronger vertical density stratification and wave steepening. In addition, the acoustic spectrum of the oscillations at the locations where magnetic perturbations are observed is broader than that observed at other locations, which suggests an additional forcing driver to the p-modes. Analysis of the photospheric oscillations in the sunspot surroundings also reveals a broader spectrum between the two opposite polarities of the active region (the leading spot and the trailing opposite polarity plage), and on the same side where magnetic perturbations are observed in the umbra. We suggest that strong photospheric perturbations between the two polarities are responsible for this broader spectrum of oscillations, with respect to the p-mode spectrum, resulting in locally excited acoustic waves that, after crossing the equipartition layer, located close to the umbra-penumbra boundary at photopheric heights, are converted into magnetic waves and steepen due to the strong density gradient.

Movie associated to Fig. 1 is available at https://www.aanda.org Title: On horizontal Poynting flux in the solar photosphere Authors: Silva, Suzana; Murabito, Mariarita; Jafarzadeh, Shahin; Stangalini, Marco; Verth, Gary; Ballai, Istvan; Fedun, Viktor Bibcode: 2021AGUFMSH44A..03S Altcode: Describing the solar atmospheric energy balance and transport is an essential step to understanding the high temperatures of the upper atmosphere. This work analyses the 3D electromagnetic energy flux in the lower atmosphere by combining Bifrost radiative MHD simulations and Sunrise/IMaX data. Based on a simulated quiet Sun atmosphere, it was found that only a minor fraction of the Poynting flux propagates upwards in the photosphere. Most of the total electromagnetic energy flows parallel to the solar surface, concentrating energy in small regions along the intergranular lanes. The dominance of the horizontal component of the electromagnetic energy flux allows an approximation for the horizontal Poynting flux, which is based solely on the horizontal velocity and the vertical magnetic field. The proxy to the horizontal Poynting flux provides a very similar distribution of the total Poynting flux and can describe the total flux for most of the photosphere with a small relative error, <30%, in regions with an intense concentration of electromagnetic energy. The results of the numerical data analysis were validated by using observational data. First, it was shown that both Bifrost and IMAX/sunrise data presents similar distributions for line-of-sight magnetic field and velocity field, indicating that the simulation realistically describes a quiet Sun region. The horizontal Poynting flux proxy provided very similar distributions for the numerical and observational data, which is considerably larger than previous observational estimates for upwards electromagnetic flux. Thereby, those findings corroborate that the electromagnetic energy flux in the photosphere is mainly parallel to the solar surface and can be properly described by approximated Poynting flux, based only on the horizontal plasma flow and the vertical magnetic field. The results also indicate that small scale intergranular motion may be important to describe the properties of Poynting flux. Therefore, further investigations based on the high-resolution data from DKIST will be important for a valuable description of the energy transport in the lower atmosphere. Title: Penumbral decay observed in active region NOAA 12585 Authors: Murabito, M.; Guglielmino, S. L.; Ermolli, I.; Romano, P.; Jafarzadeh, S.; Rouppe van der Voort, L. H. M. Bibcode: 2021A&A...653A..93M Altcode: 2021arXiv210604936M Context. The physical conditions leading the sunspot penumbra decay are poorly understood so far.
Aims: We investigate the photospheric magnetic and velocity properties of a sunspot penumbra during the decay phase to advance the current knowledge of the conditions leading to this process.
Methods: A penumbral decay was observed with the CRISP instrument at the Swedish 1 m Solar Telescope on 2016 September 4 and 5 in the active region NOAA 12585. During these days, full-Stokes spectropolarimetric scans along the Fe I 630 nm line pair were acquired over more than one hour. We inverted these observations with the VFISV code to obtain the evolution of the magnetic and velocity properties. We complement the study with data from instruments on board the Solar Dynamics Observatory and Hinode space missions.
Results: The studied penumbra disappears progressively in time and space. The magnetic flux evolution seems to be linked to the presence of moving magnetic features (MMFs). Decreasing Stokes V signals are observed. Evershed flows and horizontal fields were detected even after the disappearance of the penumbral sector.
Conclusions: The analyzed penumbral decay seems to result from the interaction between opposite polarity fields in type III MMFs and penumbra, while the presence of overlying canopies regulates the evolution in the different penumbral sectors.

Movies associated with Fig. 6 are available at https://www.aanda.org Title: A novel approach to identify resonant MHD wave modes in solar pores and sunspot umbrae: B − ω analysis Authors: Stangalini, M.; Jess, D. B.; Verth, G.; Fedun, V.; Fleck, B.; Jafarzadeh, S.; Keys, P. H.; Murabito, M.; Calchetti, D.; Aldhafeeri, A. A.; Berrilli, F.; Del Moro, D.; Jefferies, S. M.; Terradas, J.; Soler, R. Bibcode: 2021A&A...649A.169S Altcode: 2021arXiv210311639S The umbral regions of sunspots and pores in the solar photosphere are generally dominated by 3 mHz oscillations, which are due to p-modes penetrating the magnetic region. In these locations, wave power is also significantly reduced with respect to the quiet Sun. However, here we study a pore where not only is the power of the oscillations in the umbra comparable to, or even larger than, that of the quiet Sun, but the main dominant frequency is not 3 mHz as expected, but instead 5 mHz. By combining Doppler velocities and spectropolarimetry and analysing the relationship between magnetic field strength and frequency, the resultant B − ω diagram reveals distinct ridges that are remarkably clear signatures of resonant magneto-hydrodynamic (MHD) oscillations confined within the pore umbra. We demonstrate that these modes, in addition to velocity oscillations, are also accompanied by magnetic oscillations, as predicted from MHD theory. The novel technique of B − ω analysis proposed in this article opens up an exciting new avenue for identifying MHD wave modes in the umbral regions of both pores and sunspots. Title: Analysis of Pseudo-Lyapunov Exponents of Solar Convection Using State-of-the-Art Observations Authors: Viavattene, Giorgio; Murabito, Mariarita; Guglielmino, Salvatore L.; Ermolli, Ilaria; Consolini, Giuseppe; Giorgi, Fabrizio; Jafarzadeh, Shahin Bibcode: 2021Entrp..23..413V Altcode: 2021arXiv210316980V The solar photosphere and the outer layer of the Sun's interior are characterized by convective motions, which display a chaotic and turbulent character. In this work, we evaluated the pseudo-Lyapunov exponents of the overshooting convective motions observed on the Sun's surface by using a method employed in the literature to estimate those exponents, as well as another technique deduced from their definition. We analyzed observations taken with state-of-the-art instruments at ground- and space-based telescopes, and we particularly benefited from the spectro-polarimetric data acquired with the Interferometric Bidimensional Spectrometer, the Crisp Imaging SpectroPolarimeter, and the Helioseismic and Magnetic Imager. Following previous studies in the literature, we computed maps of four quantities which were representative of the physical properties of solar plasma in each observation, and estimated the pseudo-Lyapunov exponents from the residuals between the values of the quantities computed at any point in the map and the mean of values over the whole map. In contrast to previous results reported in the literature, we found that the computed exponents hold negative values, which are typical of a dissipative regime, for all the quantities derived from our observations. The values of the estimated exponents increase with the spatial resolution of the data and are almost unaffected by small concentrations of magnetic field. Finally, we showed that similar results were also achieved by estimating the exponents from residuals between the values at each point in maps derived from observations taken at different times. The latter estimation technique better accounts for the definition of these exponents than the method employed in previous studies. Title: Spectropolarimetric fluctuations in a sunspot chromosphere Authors: Stangalini, M.; Baker, D.; Valori, G.; Jess, D. B.; Jafarzadeh, S.; Murabito, M.; To, A. S. H.; Brooks, D. H.; Ermolli, I.; Giorgi, F.; MacBride, C. D. Bibcode: 2021RSPTA.37900216S Altcode: 2020arXiv200905302S The instrumental advances made in this new era of 4 m class solar telescopes with unmatched spectropolarimetric accuracy and sensitivity will enable the study of chromospheric magnetic fields and their dynamics with unprecedented detail. In this regard, spectropolarimetric diagnostics can provide invaluable insight into magneto-hydrodynamic (MHD) wave processes. MHD waves and, in particular, Alfvénic fluctuations associated with particular wave modes were recently recognized as important mechanisms not only for the heating of the outer layers of the Sun's atmosphere and the acceleration of the solar wind, but also for the elemental abundance anomaly observed in the corona of the Sun and other Sun-like stars (also known as first ionization potential) effect. Here, we take advantage of state-of-the-art and unique spectropolarimetric Interferometric BIdimensional Spectrometer observations to investigate the relation between intensity and circular polarization (CP) fluctuations in a sunspot chromosphere. Our results show a clear link between the intensity and CP fluctuations in a patch which corresponds to a narrow range of magnetic field inclinations. This suggests the presence of Alfvénic perturbations in the sunspot.

This article is part of the Theo Murphy meeting issue `High-resolution wave dynamics in the lower solar atmosphere'. Title: IBIS2.0: The new Interferometric BIdimensional Spectrometer Authors: Ermolli, Ilaria; Cirami, Roberto; Calderone, Giorgio; Del Moro, Dario; Romano, Paolo; Viavattene, Giorgio; Coretti, Igor; Giorgi, Fabrizio; Baldini, Veronica; Di Marcantonio, Paolo; Giovannelli, Luca; Guglielmino, Salvatore Luigi; Murabito, Mariarita; Pedichini, Fernando; Piazzesi, Roberto; Aliverti, Matteo; Redaelli, Edoardo Maria Alberto; Berrilli, Francesco; Zuccarello, Francesca Bibcode: 2020SPIE11447E..0ZE Altcode: We present the IBIS2.0 project, which aims to upgrade and to install the Interferometric BIdimensional Spectrometer at the solar Vacuum Tower Telescope (Tenerife, Spain) after its disassembling from the Dunn Solar Telescope (New Mexico, USA). The instrument is undergoing a hardware and software revision that will allow it to perform new spectropolarimetric measurements of the solar atmosphere at high spatial, spectral and temporal resolution in coordination with other ground- and space-based instruments. Here we present the new opto-mechanical layout and control system designed for the instrument, and describe future steps. Title: Restoring Process of Sunspot Penumbra Authors: Romano, P.; Murabito, M.; Guglielmino, S. L.; Zuccarello, F.; Falco, M. Bibcode: 2020ApJ...899..129R Altcode: 2020arXiv200609746R We describe the disappearance of a sector of sunspot penumbra and its restoring process observed in the preceding sunspot of active region NOAA 12348. The evolution of the magnetic field and the plasma flows supports the idea that the penumbra forms due to a change of inclination of the magnetic field of the canopy. Moving magnetic features have been observed during the disintegration phase of that sector of sunspot penumbra. During the restoring phase we have not observed any magnetic flux emergence around the sunspot. The restoring process of the penumbra sector completed in about 72 hr and it was accompanied by the transition from the counter-Evershed flow to the classical Evershed flow. The inversion of photospheric spectropolarimetric measurements taken by the Interferometric Bidimensional Spectroscopic Instrument (IBIS) allowed us to reconstruct how the uncombed configuration of the magnetic field forms during the new settlement of the penumbra, i.e., the vertical component of the magnetic field seems to be progressively replaced by some horizontal field lines, corresponding to the intraspines. Title: Unveiling the magnetic nature of chromospheric vortices Authors: Murabito, Mariarita; Shetye, Juie; Stangalini, Marco; Verwichte, Erwin; Arber, Tony; Ermolli, Ilaria; Giorgi, Fabrizio; Goffrey, Tom Bibcode: 2020A&A...639A..59M Altcode: 2020arXiv200613776M Context. Vortex structures in the Sun's chromosphere are believed to channel energy between different layers of the solar atmosphere.
Aims: We investigate the nature and dynamics of two small-scale quiet-Sun rotating structures in the chromosphere.
Methods: We analysed two chromospheric structures that show clear rotational patterns in spectropolarimetric observations taken with the Interferometric Bidimensional Spectrometer at the Ca II 8542 Å line.
Results: We present the detection of spectropolarimetric signals that manifest the magnetic nature of rotating structures in the chromosphere. Our observations show two long-lived structures of plasma that each rotate clockwise inside a 10 arcsec2 quiet-Sun region. Their circular polarisation signals are five to ten times above the noise level. Line-of-sight Doppler velocity and horizontal velocity maps from the observations reveal clear plasma flows at and around the two structures. A magnetohydrodynamics simulation shows these two structures are plausibly magnetically connected. Wave analysis suggests that the observed rotational vortex pattern could be due to a combination of slow actual rotation and a faster azimuthal phase speed pattern of a magnetoacoustic mode.
Conclusions: Our results imply that the vortex structures observed in the Sun's chromosphere are magnetic in nature and that they can be connected locally through the chromosphere

Movies are available at https://www.aanda.org Title: The penumbral solar filaments from the photosphere to the chromosphere Authors: Murabito, M.; Ermolli, I.; Giorgi, F.; Stangalini, M.; Guglielmino, S. L.; Jafarzadeh, S.; Socas-Navarro, H.; Romano, P.; Zuccarello, F. Bibcode: 2020JPhCS1548a2017M Altcode: The magnetic field structure of sunspots above the photosphere remain poorly understood due to limitations in observations and the complexity of these atmospheric layers. In this regard, we studied the large isolated sunspot (70”× 80”) located in the active region NOAA 12546 with spectro-polarimetric measurements acquired along the Fe I 617.3 nm and Ca II 854.2 nm lines with the IBIS/DST instrument, under excellent seeing conditions lasting more than three hours. Using the Non Local Thermodynamic Equilibrium inversion code we inverted both line measurements simultaneously to retrieve the three-dimensional magnetic and thermal structure of the penumbral region from the bottom of the photosphere to the middle chromosphere. The analysis of data acquired at spectral ranges unexplored allow us to show clear evidence of the spine and intra-spine structure of the magnetic field at chromospheric heights. In particular, we found a peak-to-peak variations of the magnetic field strength and inclination of about 200 G and 10° chromospheric heights, respectively, and of about 300 G and 20° in the photosphere. We also investigated the structure of the magnetic field gradient in the penumbra along the vertical and azimuthal directions, confirming previous results reported in the literature from data taken at the spectral region of the He I 1083 nm triplet. Title: Magnetohydrodynamic Nonlinearities in Sunspot Atmospheres: Chromospheric Detections of Intermediate Shocks Authors: Houston, S. J.; Jess, D. B.; Keppens, R.; Stangalini, M.; Keys, P. H.; Grant, S. D. T.; Jafarzadeh, S.; McFetridge, L. M.; Murabito, M.; Ermolli, I.; Giorgi, F. Bibcode: 2020ApJ...892...49H Altcode: 2020arXiv200212368H The formation of shocks within the solar atmosphere remains one of the few observable signatures of energy dissipation arising from the plethora of magnetohydrodynamic waves generated close to the solar surface. Active region observations offer exceptional views of wave behavior and its impact on the surrounding atmosphere. The stratified plasma gradients present in the lower solar atmosphere allow for the potential formation of many theorized shock phenomena. In this study, using chromospheric Ca II λ8542 line spectropolarimetric data of a large sunspot, we examine fluctuations in the plasma parameters in the aftermath of powerful shock events that demonstrate polarimetric reversals during their evolution. Modern inversion techniques are employed to uncover perturbations in the temperatures, line-of-sight velocities, and vector magnetic fields occurring across a range of optical depths synonymous with the shock formation. Classification of these nonlinear signatures is carried out by comparing the observationally derived slow, fast, and Alfvén shock solutions with the theoretical Rankine-Hugoniot relations. Employing over 200,000 independent measurements, we reveal that the Alfvén (intermediate) shock solution provides the closest match between theory and observations at optical depths of log10τ =-4, consistent with a geometric height at the boundary between the upper photosphere and lower chromosphere. This work uncovers first-time evidence of the manifestation of chromospheric intermediate shocks in sunspot umbrae, providing a new method for the potential thermalization of wave energy in a range of magnetic structures, including pores, magnetic flux ropes, and magnetic bright points. Title: Penumbral Brightening Events Observed in AR NOAA 12546 Authors: Murabito, Mariarita; Guglielmino, Salvo L.; Ermolli, Ilaria; Stangalini, Marco; Giorgi, Fabrizio Bibcode: 2020ApJ...890...96M Altcode: 2019arXiv191206002M Penumbral transient brightening events have been attributed to magnetic reconnection episodes occurring in the low corona. We investigated the trigger mechanism of these events in active region NOAA 12546 by using multiwavelength observations obtained with the Interferometric Bidimensional Spectrometer, by the Solar Dynamics Observatory, the Interface Region Imaging Spectrograph, and the Hinode satellites. We focused on the evolution of an area of the penumbra adjacent to two small-scale emerging flux regions (EFRs), which manifested three brightening events detected from the chromosphere to the corona. Two of these events correspond to B-class flares. The same region showed short-lived moving magnetic features (MMFs) that streamed out from the penumbra. In the photosphere, the EFRs led to small-scale penumbral changes associated with a counter-Evershed flow and to a reconfiguration of the magnetic fields in the moat. The brightening events had one of the footpoints embedded in the penumbra and seemed to result from the distinctive interplay between the preexisting penumbral fields, MMFs, and the EFRs. The IRIS spectra measured therein reveal enhanced temperature and asymmetries in spectral lines, suggestive of event triggering at different heights in the atmosphere. Specifically, the blue asymmetry noted in C II and Mg II h&k lines suggests the occurrence of chromospheric evaporation at the footpoint located in the penumbra as a consequence of the magnetic reconnection process at higher atmospheric heights. Title: Impact of small-scale emerging flux from the photosphere to the corona: a case study from IRIS Authors: Guglielmino, Salvo L.; Young, Peter R.; Zuccarello, Francesca; Romano, Paolo; Murabito, Mariarita Bibcode: 2020IAUS..354..439G Altcode: We report on multi-wavelength ultraviolet (UV) high-resolution observations taken with the IRIS satellite during the emergence phase of an emerging flux region embedded in the unipolar plage of active region NOAA 12529. These data are complemented by measurements taken with the spectropolarimeter aboard the Hinode satellite and by observations from SDO. Title: The 3D structure of the penumbra at high resolution from the bottom of the photosphere to the middle chromosphere Authors: Murabito, Mariarita; Ermolli, Ilaria; Giorgi, Fabrizio; Stangalini, Marco; Guglielmino, Salvo L.; Jafarzadeh, Shahin; Socas-Navarro, Hector; Romano, Paolo; Zuccarello, Francesca Bibcode: 2020IAUS..354..448M Altcode: Sunspots are the most prominent feature of the solar magnetism in the photosphere. Although they have been widely investigated in the past, their structure remains poorly understood. Indeed, due to limitations in observations and the complexity of the magnetic field estimation at chromospheric heights, the magnetic field structure of sunspot above the photosphere is still uncertain. Improving the present knowledge of sunspot is important in solar and stellar physics, since spot generation is seen not only on the Sun, but also on other solar-type stars. In this regard, we studied a large, isolated sunspot with spectro-polarimeteric measurements that were acquired at the Fe I 6173 nm and Ca II 8542 nm lines by the spectropolarimeter IBIS/DST under excellent seeing conditions lasting more than three hours. Using the Non-LTE inversion code NICOLE, we inverted both line measurements simultaneously, to retrieve the three-dimensional magnetic and thermal structure of the penumbral region from the bottom of the photosphere to the middle chromosphere. Our analysis of data acquired at spectral ranges unexplored in previous studies shows clear spine and intra-spine structure of the penumbral magnetic field at chromopheric heights. Our investigation of the magnetic field gradient in the penumbra along the vertical and azimuthal directions confirms results reported in the literature from analysis of data taken at the spectral region of the He I 1083 nm triplet. Title: Continuum Enhancements, Line Profiles, and Magnetic Field Evolution during Consecutive Flares Authors: Zuccarello, Francesca; Guglielmino, Salvo L.; Capparelli, Vincenzo; Mathioudakis, Mihalis; Keys, Peter H.; Criscuoli, Serena; Falco, Mariachiara; Murabito, Mariarita Bibcode: 2020ApJ...889...65Z Altcode: 2019arXiv191200859Z During solar flares, magnetic energy can be converted into electromagnetic radiation from radio waves to γ-rays. Enhancements in the continuum at visible wavelengths, as well as continuum enhancements in the FUV and NUV passbands, give rise to white-light flares. In addition, the strong energy release in these events can lead to the rearrangement of the magnetic field at the photospheric level, causing morphological changes in large and stable magnetic structures like sunspots. In this context, we describe observations acquired by satellite instruments (Interface Region Imaging Spectrograph (IRIS), Solar Dynamics Observatory/Helioseismic and Magnetic Imager, Hinode/Solar Optical Telescope) and ground-based telescopes (Rapid Oscillations in the Solar Atmosphere (ROSA)/Dunn Solar Telescope) during two consecutive C7.0 and X1.6 flares that occurred in active region NOAA 12205 on 2014 November 7. The flare was accompanied by an eruption. The results of the analysis show the presence of continuum enhancements during the evolution of the events, observed both in ROSA images and in IRIS spectra. In the latter, a prominent blueshifted component is observed at the onset of the eruption. We investigate the role played by the evolution of the δ sunspots of the active region in the flare triggering, and finally we discuss the changes in the penumbrae surrounding these sunspots as a further consequence of these flares. Title: Properties of the Umbral Filament Observed in Active Region NOAA 12529 Authors: Guglielmino, Salvo L.; Romano, Paolo; Ruiz Cobo, Basilio; Zuccarello, Francesca; Murabito, Mariarita Bibcode: 2019ApJ...880...34G Altcode: 2019arXiv190600065G Recent observations of the solar photosphere revealed the presence of elongated filamentary bright structures inside sunspot umbrae, called umbral filaments (UFs). These features differ in morphology, magnetic configuration, and evolution from light bridges (LBs) that are usually observed to intrude in sunspots. To characterize a UF observed in the umbra of the giant leading sunspot of active region NOAA 12529, we analyze high-resolution observations taken in the photosphere with the spectropolarimeter on board the Hinode satellite and in the upper chromosphere and transition region with the IRIS telescope. The results of this analysis definitely rule out the hypothesis that the UF might be a kind of LB. In fact, we find no field-free or low-field strength region cospatial to the UF. Conversely, we recognize the presence of a strong horizontal field larger than 2500 G, a significant portion of the UF with opposite polarity with respect to the surroundings, and filaments in the upper atmospheric layers corresponding to the UF in the photosphere. These findings suggest that this structure is the photospheric manifestation of a flux rope hanging above the sunspot and forming penumbral-like filaments within the umbra via magneto-convection. This reinforces a previously proposed scenario. Title: Formation of the Penumbra and Start of the Evershed Flow Authors: Murabito, M.; Romano, P.; Guglielmino, S. L.; Zuccarello, F.; Solanki, S. K. Bibcode: 2019ASPC..526..243M Altcode: We analyze high-resolution observations of Active Region NOAA 11490, acquired on 2012 May 28 and 29. Spectropolarimetric measurements of the photospheric lines of Fe I at 617.3 nm and 630.25 nm were taken with the Interferometric BIdimensional Spectrometer (IBIS), mounted on NSO/DST, during about 30 minutes for each day. To study the evolution of continuum intensity, LOS velocity, inclination and strength of the magnetic field during the entire time interval, we also used data taken by SDO/HMI. We used the SIR code to invert the Stokes profiles observed with IBIS, using different initial models to take into account the physical conditions of the plasma in the region of umbra, penumbra, and quiet Sun. From the analysis of the SIR results, we found that, before the formation of the penumbra, the annular zone is characterized by downflows in the inner part. Furthermore, we observed that the onset of the classical Evershed flow occurs on a short time scale, 1-3 hours, while the penumbra is forming. In order to investigate the conditions that lead to the establishment of the classical Evershed flow, we analyzed the evolution of the continuum intensity, LOS velocity, inclination and strength of the magnetic field in a segment in the north-western part of the leading spot. In about 1 hour, we noted a clear evolution from redshift to blueshift in the penumbral filaments along the selected segment. We propose a scenario in which the penumbra is formed by magnetic flux dragged down from the canopy surrounding the initial pore: the Evershed flow starts when the sinking magnetic field dips below the solar surface and magnetoconvection sets in. Title: Height Dependence of the Penumbral Fine-scale Structure in the Inner Solar Atmosphere Authors: Murabito, Mariarita; Ermolli, I.; Giorgi, F.; Stangalini, M.; Guglielmino, S. L.; Jafarzadeh, S.; Socas-Navarro, H.; Romano, P.; Zuccarello, F. Bibcode: 2019ApJ...873..126M Altcode: 2018arXiv181209029M We studied the physical parameters of the penumbra in a large and fully developed sunspot, one of the largest over the last two solar cycles, by using full-Stokes measurements taken at the photospheric Fe I 617.3 nm and chromospheric Ca II 854.2 nm lines with the Interferometric Bidimensional Spectrometer. Inverting measurements with the Non-LTE inversion COde (NICOLE) code, we obtained the three-dimensional structure of the magnetic field in the penumbra from the bottom of the photosphere up to the middle chromosphere. We analyzed the azimuthal and vertical gradient of the magnetic field strength and inclination. Our results provide new insights on the properties of the penumbral magnetic fields in the chromosphere at atmospheric heights unexplored in previous studies. We found signatures of the small-scale spine and intraspine structure of both the magnetic field strength and inclination at all investigated atmospheric heights. In particular, we report typical peak-to-peak variations of the field strength and inclination of ≈300 G and ≈20°, respectively, in the photosphere, and of ≈200 G and ≈10° in the chromosphere. In addition, we estimated the vertical gradient of the magnetic field strength in the studied penumbra: we find a value of ≈0.3 G km-1 between the photosphere and the middle chromosphere. Interestingly, the photospheric magnetic field gradient changes sign from negative in the inner to positive in the outer penumbra. Title: New atmosphere models to reconstruct solar irradiance Authors: Ermolli, I.; Murabito, M.; Stangalini, M.; Giorgi, F. Bibcode: 2019NCimC..42....4E Altcode: We aim at contributing to the refinement of the atmosphere models employed in solar irradiance reconstructions by deriving observation-based atmospheres from spectropolarimetric measurements of the solar atmosphere. Here we present results obtained from analysis of photospheric and chromospheric observations of quiet Sun, umbral, and penumbral regions, performed on May 20th 2016 with the IBIS Interferometric Bidimensional Spectrometer under excellent seeing conditions. Title: High-resolution observations of the umbral filament in AR NOAA 12529 Authors: Guglielmino, S. L.; Romano, P.; Ruiz Cobo, B.; Zuccarello, , F.; Murabito, M. Bibcode: 2019NCimC..42...12G Altcode: Recent observations have shown in some sunspots the presence of structures that have been called umbral filaments (UFs). These consist of bright filamentary features intruding sunspot umbrae, different in morphology, evolution, and magnetic configuration from usually observed light bridges. We report on the properties of an UF observed inside the umbra of the giant leading sunspot in active region NOAA 12529. We analysed high-resolution observations taken in the photosphere with the spectropolarimeter aboard the Hinode satellite and in the upper chromosphere and transition region with the IRIS telescope. These observations were complemented with data from the Solar Dynamic Observatory satellite and from the INAF-OACT equatorial spar to study the evolution of this structure. We find that the UF harbours a strong horizontal component of the magnetic field and a portion with polarity opposite with respect to that of the umbra. In the upper atmospheric layers, the structure is cospatial to a bundle of filaments, which appears to be rooted in the sunspot umbra. We propose that the UF is the photospheric counterpart of a flux rope touching the sunspot and giving rise to penumbral-like filaments in the umbra via magneto-convection. Title: Continuum emission enhancements and penumbral changes observed during flares by IRIS, ROSA, and Hinode Authors: Zuccarello, F.; Guglielmino, S. L.; Capparelli, V.; Mathioudakis, M.; Keys, P.; Fletcher, L.; Criscuoli, S.; Falco, M.; Murabito, M. Bibcode: 2019NCimC..42...13Z Altcode: 2019arXiv190101732Z In this paper we describe observations acquired by satellite instruments ( Hinode/SOT and IRIS) and ground-based telescopes (ROSA@DST) during two consecutive C7.0 and X1.6 flares occurred in active region NOAA 12205 on 2014 November 7. The analysis of these data show the presence of continuum enhancements during the evolution of the events, observed both in ROSA images and in IRIS spectra. Moreover, we analyze the role played by the evolution of the δ sunspots of the active region in the flare triggering, indicating the disappearance of a large portion of penumbra around these sunspots. Title: Satellite observations of reconnection between emerging and pre-existing small-scale magnetic fields Authors: Guglielmino, S. L.; Zuccarello, F.; Young, P. R.; Romano, P.; Murabito, M. Bibcode: 2019NCimC..42...33G Altcode: 2019arXiv190101056G We report multi-wavelength ultraviolet observations taken with the IRIS satellite, concerning the emergence phase in the upper chromosphere and transition region of an emerging flux region (EFR) embedded in the unipolar plage of active region NOAA 12529. The photospheric configuration of the EFR is analyzed in detail benefitting from measurements taken with the spectropolarimeter aboard the Hinode satellite, when the EFR was fully developed. In addition, these data are complemented by full-disk, simultaneous observations of the SDO satellite, relevant to the photosphere and the corona. In the photosphere, magnetic flux emergence signatures are recognized in the fuzzy granulation, with dark alignments between the emerging polarities, cospatial with highly inclined fields. In the upper atmospheric layers, we identify recurrent brightenings that resemble UV bursts, with counterparts in all coronal passbands. These occur at the edges of the EFR and in the region of the arch filament system (AFS) cospatial to the EFR. Jet activity is also found at chromospheric and coronal levels, near the AFS and the observed brightness enhancement sites. The analysis of the IRIS line profiles reveals the heating of dense plasma in the low solar atmosphere and the driving of bi-directional high-velocity flows with speeds up to 100 km/s at the same locations. Furthermore, we detect a correlation between the Doppler velocity and line width of the Si IV 1394 and 1402 Å line profiles in the UV burst pixels and their skewness. Comparing these findings with previous observations and numerical models, we suggest evidence of several long-lasting, small-scale magnetic reconnection episodes between the emerging bipole and the ambient field. This process leads to the cancellation of a pre-existing photospheric flux concentration of the plage with the opposite polarity flux patch of the EFR. The reconnection appears to occur higher in the atmosphere than usually observed. Title: Recent insights on the penumbra formation process Authors: Murabito, M.; Romano, P.; Zuccarello, F.; Guglielmino, S. L. Bibcode: 2019NCimC..42...11M Altcode: 2019arXiv190105207M Using high-resolution spectropolarimetric data acquired by IBIS, as well as SDO/HMI observations, we studied the penumbra formation in AR NOAA 11490 and in a sample of twelve ARs appeared on the solar disk on 2011 and 2012, which were characterized by β -type magnetic field configuration. The results show that the onset of the classical Evershed flow occurs in a very short time scale, 1-3 hours. Studying the formation of the first penumbral sector around the following proto-spot, we found that a stable penumbra forms in the area facing the opposite polarity, which appears to be co-spatial with an AFS, i.e. in a flux emergence region, in contrast with the results of the paper SCHLICHENMAIER R., REZAEI R. ET AL., Astron. Astrophys., 512 (2010) L1 concerning the leading polarity of AR NOAA 11490. Conversely, analyzing the sample of twelve ARs, we noticed that there is not a preferred location for the formation of the first penumbral sector. We also observed before the penumbra formation an inverse Evershed flow, which changes its sign when the penumbra appears. This confirms the observational evidence that the appearance of the penumbral filaments is correlated with the transition from the inverse Evershed to the classical Evershed flow. Furthermore, the analysis suggests that the time needed to form the penumbra may be related to the location where the penumbra first appears. New high-resolution observations, like those that will be provided by the European Solar Telescope, are expected to increase our understanding of the penumbra formation process. Title: Propagating Spectropolarimetric Disturbances in a Large Sunspot Authors: Stangalini, M.; Jafarzadeh, S.; Ermolli, I.; Erdélyi, R.; Jess, D. B.; Keys, P. H.; Giorgi, F.; Murabito, M.; Berrilli, F.; Del Moro, D. Bibcode: 2018ApJ...869..110S Altcode: 2018arXiv181012595S We present results derived from the analysis of spectropolarimetric measurements of active region AR12546, which represents one of the largest sunspots to have emerged onto the solar surface over the last 20 years. The region was observed with full-Stokes scans of the Fe I 617.3 nm and Ca II 854.2 nm lines with the Interferometric BIdimensional Spectrometer instrument at the Dunn Solar Telescope over an uncommon, extremely long time interval exceeding three hours. Clear circular polarization (CP) oscillations localized at the umbra-penumbra boundary of the observed region were detected. Furthermore, the multi-height data allowed us to detect the downward propagation of both CP and intensity disturbances at 2.5-3 mHz, which was identified by a phase delay between these two quantities. These results are interpreted as a propagating magnetohydrodynamic surface mode in the observed sunspot. Title: IRIS Observations of Magnetic Interactions in the Solar Atmosphere between Preexisting and Emerging Magnetic Fields. I. Overall Evolution Authors: Guglielmino, Salvo L.; Zuccarello, Francesca; Young, Peter R.; Murabito, Mariarita; Romano, Paolo Bibcode: 2018ApJ...856..127G Altcode: 2018arXiv180205657G We report multiwavelength ultraviolet observations taken with the IRIS satellite, concerning the emergence phase in the upper chromosphere and transition region of an emerging flux region (EFR) embedded in the preexisting field of active region NOAA 12529 in the Sun. IRIS data are complemented by full-disk observations of the Solar Dynamics Observatory satellite, relevant to the photosphere and the corona. The photospheric configuration of the EFR is also analyzed by measurements taken with the spectropolarimeter on board the Hinode satellite, when the EFR was fully developed. Recurrent intense brightenings that resemble UV bursts, with counterparts in all coronal passbands, are identified at the edges of the EFR. Jet activity is also observed at chromospheric and coronal levels, near the observed brightenings. The analysis of the IRIS line profiles reveals the heating of dense plasma in the low solar atmosphere and the driving of bidirectional high-velocity flows with speed up to 100 km s-1 at the same locations. Compared with previous observations and numerical models, these signatures suggest evidence of several long-lasting, small-scale magnetic reconnection episodes between the emerging bipole and the ambient field. This process leads to the cancellation of a preexisting photospheric flux concentration and appears to occur higher in the atmosphere than usually found in UV bursts, explaining the observed coronal counterparts. Title: Formation of Penumbra in a Sample of Active Regions Observed by the SDO Satellite Authors: Murabito, Mariarita; Zuccarello, Francesca; Guglielmino, Salvo L.; Romano, Paolo Bibcode: 2018ApJ...855...58M Altcode: Recently, high-resolution observations improved our understanding of the penumbra formation process around sunspots. In particular, two aspects have been carefully investigated: whether the settlement of the penumbra can occur between the main opposite magnetic polarities where new magnetic flux is still emerging, and the establishment of the Evershed flow. In this paper, we present the analysis of twelve active regions (ARs) where both the penumbra formation and the onset of the Evershed flow were observed. We used data acquired by the Helioseismic and Magnetic Imager (HMI) instrument on board the Solar Dynamic Observatory (SDO) satellite analyzing continuum images, magnetograms, and Dopplergrams of the selected ARs. The results obtained in our sample provided the following information about the stable settlement of the penumbra: eight spots formed the first stable penumbral sector in the region between the two opposite polarities, and nine spots formed on the opposite side. Moreover, eleven sunpots showed an inverse Evershed flow (i.e., a plasma motion directed toward the protospot border) before the penumbra formation, which changes within 1-6 hr into the classical Evershed flow as soon as the penumbra forms. Comparing our results with recent observations, we are able to discriminate between the different ways of penumbra formation. Moreover, we suggest that the change from inverse Evershed flow, visible before the penumbra appears, into the classical Evershed flow may be a signature of the formation of penumbral filaments. Title: Long-term optical monitoring of the solar atmosphere in Italy Authors: Guglielmino, S. L.; Ermolli, I.; Romano, P.; Zuccarello, F.; Giorgi, F.; Falco, M.; Piazzesi, R.; Stangalini, M.; Murabito, M.; Ferrucci, M.; Mangano, A. Bibcode: 2018IAUS..340..251G Altcode: 2019arXiv190101050G Probably, the long-term monitoring of the solar atmosphere started in Italy with the first telescopic observations of the Sun made by Galileo Galilei in the early 17th century. His recorded observations and science results, as well as the work carried out by other following outstanding Italian astronomers inspired the start of institutional programs of regular solar observations at the Arcetri, Catania, and Rome Observatories.

These programs have accumulated daily images of the solar photosphere and chromosphere taken at various spectral bands over a time span larger than 80 years. In the last two decades, regular solar observations were continued with digital cameras only at the Catania and Rome Observatories, which are now part of the INAF National Institute for Astrophysics. At the two sites, daily solar images are taken at the photospheric G-band, Blue (λ = 409.4 nm), and Red (λ = 606.9 nm) continua spectral ranges and at the chromospheric Ca II K and Hα lines, with a 2'' spatial resolution.

Solar observation in Italy, which benefits from over 2500 hours of yearly sunshine, currently aims at the operational monitoring of solar activity and long-term variability and at the continuation of the historical series as well. Existing instruments will be soon enriched by the SAMM double channel telescope equipped with magneto-optical filters that will enable the tomography of the solar atmosphere with simultaneous observations at the K I 769.9 nm and Na I D 589.0 nm lines. In this contribution, we present the available observations and outline their scientific relevance. Title: Observation of a 3D Magnetic Null Point Authors: Romano, P.; Falco, M.; Guglielmino, S. L.; Murabito, M. Bibcode: 2017ApJ...837..173R Altcode: 2017arXiv170300665R We describe high-resolution observations of a GOES B-class flare characterized by a circular ribbon at the chromospheric level, corresponding to the network at the photospheric level. We interpret the flare as a consequence of a magnetic reconnection event that occurred at a three-dimensional (3D) coronal null point located above the supergranular cell. The potential field extrapolation of the photospheric magnetic field indicates that the circular chromospheric ribbon is cospatial with the fan footpoints, while the ribbons of the inner and outer spines look like compact kernels. We found new interesting observational aspects that need to be explained by models: (1) a loop corresponding to the outer spine became brighter a few minutes before the onset of the flare; (2) the circular ribbon was formed by several adjacent compact kernels characterized by a size of 1″-2″ (3) the kernels with a stronger intensity emission were located at the outer footpoint of the darker filaments, departing radially from the center of the supergranular cell; (4) these kernels started to brighten sequentially in clockwise direction; and (5) the site of the 3D null point and the shape of the outer spine were detected by RHESSI in the low-energy channel between 6.0 and 12.0 keV. Taking into account all these features and the length scales of the magnetic systems involved in the event, we argue that the low intensity of the flare may be ascribed to the low amount of magnetic flux and to its symmetric configuration. Title: On the Formation of a Stable Penumbra in a Region of Flux Emergence in the Sun Authors: Murabito, M.; Romano, P.; Guglielmino, S. L.; Zuccarello, F. Bibcode: 2017ApJ...834...76M Altcode: 2016arXiv161104749M We studied the formation of the first penumbral sector around a pore in the following polarity of the NOAA Active Region (AR) 11490. We used a high spatial, spectral, and temporal resolution data set acquired by the Interferometric BIdimensional Spectrometer operating at the NSO/Dunn Solar Telescope, as well as data taken by the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory satellite. On the side toward the leading polarity, elongated granules in the photosphere and an arch filament system (AFS) in the chromosphere are present, while the magnetic field shows a sea-serpent configuration, indicating a region of magnetic flux emergence. We found that the formation of a stable penumbra in the following polarity of the AR begins in the area facing the opposite polarity located below the AFS in the flux emergence region, different from what was found by Schlichenmaier and colleagues. Moreover, during the formation of the first penumbral sector, the area characterized by magnetic flux density larger than 900 G and the area of the umbra increase. Title: Polarization signatures in the chromosphere during an X1.6 flare Authors: Guglielmino, S. L.; Zuccarello, F.; Murabito, M.; Romano, P. Bibcode: 2017psio.confE.119G Altcode: No abstract at ADS Title: Formation of a stable penumbra in a region of flux emergence Authors: Murabito, Mariarita Bibcode: 2017psio.confE..52M Altcode: No abstract at ADS Title: Formation of the Penumbra and Start of the Evershed Flow Authors: Murabito, M.; Romano, P.; Guglielmino, S. L.; Zuccarello, F.; Solanki, S. K. Bibcode: 2016ApJ...825...75M Altcode: 2016arXiv160405610M We studied the variations of line of sight photospheric plasma flows during the formation phase of the penumbra around a pore in active region NOAA 11490. We used a high spatial, spectral, and temporal resolution data set acquired by the Interferometric BIdimensional Spectrometer operating at the NSO/Dunn Solar Telescope as well as data taken by the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory satellite (SDO/HMI). Before the penumbra formed we observed a redshift of the spectral line in the inner part of the annular zone surrounding the pore as well as a blueshift of material associated with opposite magnetic polarity farther away from the pore. We found that the onset of the classical Evershed flow occurs on a very short timescale (1 to 3 hr) while the penumbra is forming. During the same time interval we found changes in the magnetic field inclination in the penumbra, with the vertical field actually changing sign near the penumbral edge, while the total magnetic field showed a significant increase, about 400 G. To explain these and other observations related to the formation of the penumbra and the onset of the Evershed flow we propose a scenario in which the penumbra is formed by magnetic flux dragged down from the canopy surrounding the initial pore. The Evershed flow starts when the sinking magnetic field dips below the solar surface and magnetoconvection sets in.