Abstract A new searching algorithm to find voids in high resolution magnetograms is described. Th... more Abstract A new searching algorithm to find voids in high resolution magnetograms is described. This algorithm permits the investigation of spatially intermittent nature of magnetic field emerging when solar surface is observed at high spatial resolution. Actually, at these small scales, the connected patterns, forming magnetic network, show aligned or clustered magnetic features producing a highly branched and fractal pattern embodying magnetic elements.
Abstract Movies of magnetograms of sunspots often show small-size magnetic patches that move radi... more Abstract Movies of magnetograms of sunspots often show small-size magnetic patches that move radially away and seem to be expelled from the field of the spot. These patches are named Moving Magnetic Features (MMFs). They have been mostly observed around spots and have been interpreted as manifestations of penumbral filaments. Nevertheless, few observations of MMFS streaming out from spots without penumbra have been reported.
Abstract We present the results from the SIR inversion of spectropolarimetric data acquired with ... more Abstract We present the results from the SIR inversion of spectropolarimetric data acquired with the IBIS (Interferometric BIdimensional Spectrometer) instrument at the NSO Dunn Solar Telescope, Sacramento Peak (NM, USA). The inversion analysis is performed on Stokes I and V profiles measured in the two FeI visible lines at 630 nm over a (~ 40 x 40 Mm) quiet Sun portion, for a time interval of 53 minutes. The noise level for Stokes V profiles is 0.003 the continuum intensity.
ABSTRACT A forecasting algorithm (FORS) based on Auto Regressive Moving Average (ARMA) processes ... more ABSTRACT A forecasting algorithm (FORS) based on Auto Regressive Moving Average (ARMA) processes was developed to correctly model stationary processes and was applied in simulations to the problem of improving the efficiency of an adaptive optics (AO) system. We present here a hardware demonstrator developed at the Solar Physics Laboratory of the University of Rome Tor Vergata where this algorithm has been implemented.
ABSTRACT The Doppler-Intensity-Magnetograms with a Magneto-optical filter Instrument at two heigh... more ABSTRACT The Doppler-Intensity-Magnetograms with a Magneto-optical filter Instrument at two heights (DIMMI-2h) is a double channel imager using Magneto Optical Filters (MOF) in the potassium 770 nm and sodium 589 nm lines. The instrument will provide simultaneous dopplergrams (velocity fields), continuum intensity and longitudinal magnetic flux images at two heights in the solar atmosphere corresponding to low and high photosphere. Dimmi-2h is the possible piggy-back payload on ADAHELI satellite.
Abstract IBIS (Interferometric BIdimensional Spectrometer) allows us to measure the four Stokes p... more Abstract IBIS (Interferometric BIdimensional Spectrometer) allows us to measure the four Stokes parameters in several spectroscopic lines with high spatial and spectral resolutions. With this information, we can retrieve both the dynamics and the magnetic field at different layers of the Photosphere and Chromosphere. The high spectral, spatial and temporal resolutions and the polarimetric sensitivity of IBIS allows us to study different phenomena taking place in the solar atmosphere with new tools.
Abstract. Fabry-Pérot tunable filters are of great interest in high spectral resolution imaging f... more Abstract. Fabry-Pérot tunable filters are of great interest in high spectral resolution imaging for both ground-based and space astronomical observations. Major advantages include imaging capabilities and the study of extended astronomical sources, such as the solar photosphere. The high transparency of the instrument allows the high time-resolution necessary for the observation of fast dynamic processes.
ABSTRACT In this contribution we present preliminary mechanical and optical tests of the Fabry-Pé... more ABSTRACT In this contribution we present preliminary mechanical and optical tests of the Fabry-Pérot interferometer prototype developed at the “Tor Vergata” University Solar Physics Laboratory. Fabry-Pérot narrow filters are of great interest for the study of extended astronomical sources, such as the solar photosphere and chromosphere. The high transparency of the instrument allows for the necessary high time-resolution for fast dynamic processes observations.
ABSTRACT Statistical properties of flares are a powerful tool for addressing the upper solar atmo... more ABSTRACT Statistical properties of flares are a powerful tool for addressing the upper solar atmosphere heating problem. We simulate time series of synthetic flares by means of a dynamic model of the atmospheric magnetic field in which magnetic loop footpoints are controlled by photospheric flows computed through a n-body algorithm.
ABSTRACT We present an overview of the conceptual design of the data handling unit of the ECS, th... more ABSTRACT We present an overview of the conceptual design of the data handling unit of the ECS, the Control System for the European Solar Telescope (EST). We will focus on describing the critical requirements for this unit resulting from the overall design of the telescope, together with its architecture and the results of the feasibility analysis carried out to date. Keywords: solar telescope, EST, telescope control, control software
Abstract A real time flare searching system has been developed at the University of Tor Vergata. ... more Abstract A real time flare searching system has been developed at the University of Tor Vergata. The system is comprised of a CMOS camera (C-CAM BCi5) which captures full disk H-alpha solar images and a detection algorithm. The system has been installed for test at the Solar Station of the Tor Vergata University. The algorithm detects in real time the onset of solar flares by analysing intensity variations in the images. The basic parameters for the definition of a flare onset (intensity gradient and threshold) are user-tunable.
Abstract The Energetic Particle Detector (EPD) on board the Solar Orbiter represents an excellent... more Abstract The Energetic Particle Detector (EPD) on board the Solar Orbiter represents an excellent chance to study Solar Energetic Particles, solar modulation effects and cosmic ray gradients from an unique observation point. The development of silicon detector technology and electronics allows the nuclear and isotopic components of solar and galactic cosmic rays to be studied in growing detail.
Abstract We present results from observations of Moving Magnetic Features (MMFs) of different typ... more Abstract We present results from observations of Moving Magnetic Features (MMFs) of different types observed on region NOAA 11005. The analyses is based on spectro-polarimetric data obtained with the Interferometric Bidimensional Spectrometer (IBIS) at various spectral ranges. We present new evidences of bipolar MMFs observed to stream out from pores and show the temporal evolution of magnetic, dynamic and morphological properties of these features.
ABSTRACT A consortium of more than 20 European solar physics institution from 15 different countr... more ABSTRACT A consortium of more than 20 European solar physics institution from 15 different countries is conducting a design study for a 4 m class solar telescope which shall be situated at the Canary Islands. In this paper we introduce the AO and MCAO design concept for EST. A ground layer deformable mirror is combined with an arrangement of four deformable layer mirrors.
abstract A study is presented for the realization of the heat stop for the 4-m European Solar Tel... more abstract A study is presented for the realization of the heat stop for the 4-m European Solar Telescope EST, whose feasibility study will be completed in 2011. EST is an on-axis Gregorian telescope, equipped with a four-meter diameter primary mirror and primary focal length of about six meters. The heat stop, positioned at the primary focus, must be able to remove a heat load of 13 kW, while maintaining its surfaces very close to room temperature, to avoid the onset of seeing.
Abstract The spatial configuration of enhanced magnetic field (active regions) in the outer layer... more Abstract The spatial configuration of enhanced magnetic field (active regions) in the outer layers of the Sun derives from the interaction between convective flows and solar magnetic field. Temporal evolution of active regions is considered the main responsible of radiative output variations. Particularly, solar irradiance variations are explained in terms of temporal and spatial evolution of solar surface magnetic fields.
Abstract. We investigate the spatial distribution of reticular clusters of magnetic features on t... more Abstract. We investigate the spatial distribution of reticular clusters of magnetic features on the solar surface. For this purpose, we develop a void searching algorithm, such as those used in cosmology to study galaxy spatial distributions. We apply this method to a temporal series of large FoV MDI (Michelson Doppler Imager) magnetograms, to identify voids between magnetic structures and to extract their normalized Void Probability Function, which characterizes the scale distribution of magnetic inter-cluster voids.
Abstract We present a comparative study of photometric and dynamic properties of photospheric bri... more Abstract We present a comparative study of photometric and dynamic properties of photospheric bright points (BPs) observed at the disk centre in the active region (AR) NOAA 10912 and in the quiet Sun. We found that the average concentration of BPs is 54% larger in the AR than in the quiet Sun. We also measure a decrease of the BP concentration and an increase of their size moving away from the AR centre.
Abstract A new searching algorithm to find voids in high resolution magnetograms is described. Th... more Abstract A new searching algorithm to find voids in high resolution magnetograms is described. This algorithm permits the investigation of spatially intermittent nature of magnetic field emerging when solar surface is observed at high spatial resolution. Actually, at these small scales, the connected patterns, forming magnetic network, show aligned or clustered magnetic features producing a highly branched and fractal pattern embodying magnetic elements.
Abstract Movies of magnetograms of sunspots often show small-size magnetic patches that move radi... more Abstract Movies of magnetograms of sunspots often show small-size magnetic patches that move radially away and seem to be expelled from the field of the spot. These patches are named Moving Magnetic Features (MMFs). They have been mostly observed around spots and have been interpreted as manifestations of penumbral filaments. Nevertheless, few observations of MMFS streaming out from spots without penumbra have been reported.
Abstract We present the results from the SIR inversion of spectropolarimetric data acquired with ... more Abstract We present the results from the SIR inversion of spectropolarimetric data acquired with the IBIS (Interferometric BIdimensional Spectrometer) instrument at the NSO Dunn Solar Telescope, Sacramento Peak (NM, USA). The inversion analysis is performed on Stokes I and V profiles measured in the two FeI visible lines at 630 nm over a (~ 40 x 40 Mm) quiet Sun portion, for a time interval of 53 minutes. The noise level for Stokes V profiles is 0.003 the continuum intensity.
ABSTRACT A forecasting algorithm (FORS) based on Auto Regressive Moving Average (ARMA) processes ... more ABSTRACT A forecasting algorithm (FORS) based on Auto Regressive Moving Average (ARMA) processes was developed to correctly model stationary processes and was applied in simulations to the problem of improving the efficiency of an adaptive optics (AO) system. We present here a hardware demonstrator developed at the Solar Physics Laboratory of the University of Rome Tor Vergata where this algorithm has been implemented.
ABSTRACT The Doppler-Intensity-Magnetograms with a Magneto-optical filter Instrument at two heigh... more ABSTRACT The Doppler-Intensity-Magnetograms with a Magneto-optical filter Instrument at two heights (DIMMI-2h) is a double channel imager using Magneto Optical Filters (MOF) in the potassium 770 nm and sodium 589 nm lines. The instrument will provide simultaneous dopplergrams (velocity fields), continuum intensity and longitudinal magnetic flux images at two heights in the solar atmosphere corresponding to low and high photosphere. Dimmi-2h is the possible piggy-back payload on ADAHELI satellite.
Abstract IBIS (Interferometric BIdimensional Spectrometer) allows us to measure the four Stokes p... more Abstract IBIS (Interferometric BIdimensional Spectrometer) allows us to measure the four Stokes parameters in several spectroscopic lines with high spatial and spectral resolutions. With this information, we can retrieve both the dynamics and the magnetic field at different layers of the Photosphere and Chromosphere. The high spectral, spatial and temporal resolutions and the polarimetric sensitivity of IBIS allows us to study different phenomena taking place in the solar atmosphere with new tools.
Abstract. Fabry-Pérot tunable filters are of great interest in high spectral resolution imaging f... more Abstract. Fabry-Pérot tunable filters are of great interest in high spectral resolution imaging for both ground-based and space astronomical observations. Major advantages include imaging capabilities and the study of extended astronomical sources, such as the solar photosphere. The high transparency of the instrument allows the high time-resolution necessary for the observation of fast dynamic processes.
ABSTRACT In this contribution we present preliminary mechanical and optical tests of the Fabry-Pé... more ABSTRACT In this contribution we present preliminary mechanical and optical tests of the Fabry-Pérot interferometer prototype developed at the “Tor Vergata” University Solar Physics Laboratory. Fabry-Pérot narrow filters are of great interest for the study of extended astronomical sources, such as the solar photosphere and chromosphere. The high transparency of the instrument allows for the necessary high time-resolution for fast dynamic processes observations.
ABSTRACT Statistical properties of flares are a powerful tool for addressing the upper solar atmo... more ABSTRACT Statistical properties of flares are a powerful tool for addressing the upper solar atmosphere heating problem. We simulate time series of synthetic flares by means of a dynamic model of the atmospheric magnetic field in which magnetic loop footpoints are controlled by photospheric flows computed through a n-body algorithm.
ABSTRACT We present an overview of the conceptual design of the data handling unit of the ECS, th... more ABSTRACT We present an overview of the conceptual design of the data handling unit of the ECS, the Control System for the European Solar Telescope (EST). We will focus on describing the critical requirements for this unit resulting from the overall design of the telescope, together with its architecture and the results of the feasibility analysis carried out to date. Keywords: solar telescope, EST, telescope control, control software
Abstract A real time flare searching system has been developed at the University of Tor Vergata. ... more Abstract A real time flare searching system has been developed at the University of Tor Vergata. The system is comprised of a CMOS camera (C-CAM BCi5) which captures full disk H-alpha solar images and a detection algorithm. The system has been installed for test at the Solar Station of the Tor Vergata University. The algorithm detects in real time the onset of solar flares by analysing intensity variations in the images. The basic parameters for the definition of a flare onset (intensity gradient and threshold) are user-tunable.
Abstract The Energetic Particle Detector (EPD) on board the Solar Orbiter represents an excellent... more Abstract The Energetic Particle Detector (EPD) on board the Solar Orbiter represents an excellent chance to study Solar Energetic Particles, solar modulation effects and cosmic ray gradients from an unique observation point. The development of silicon detector technology and electronics allows the nuclear and isotopic components of solar and galactic cosmic rays to be studied in growing detail.
Abstract We present results from observations of Moving Magnetic Features (MMFs) of different typ... more Abstract We present results from observations of Moving Magnetic Features (MMFs) of different types observed on region NOAA 11005. The analyses is based on spectro-polarimetric data obtained with the Interferometric Bidimensional Spectrometer (IBIS) at various spectral ranges. We present new evidences of bipolar MMFs observed to stream out from pores and show the temporal evolution of magnetic, dynamic and morphological properties of these features.
ABSTRACT A consortium of more than 20 European solar physics institution from 15 different countr... more ABSTRACT A consortium of more than 20 European solar physics institution from 15 different countries is conducting a design study for a 4 m class solar telescope which shall be situated at the Canary Islands. In this paper we introduce the AO and MCAO design concept for EST. A ground layer deformable mirror is combined with an arrangement of four deformable layer mirrors.
abstract A study is presented for the realization of the heat stop for the 4-m European Solar Tel... more abstract A study is presented for the realization of the heat stop for the 4-m European Solar Telescope EST, whose feasibility study will be completed in 2011. EST is an on-axis Gregorian telescope, equipped with a four-meter diameter primary mirror and primary focal length of about six meters. The heat stop, positioned at the primary focus, must be able to remove a heat load of 13 kW, while maintaining its surfaces very close to room temperature, to avoid the onset of seeing.
Abstract The spatial configuration of enhanced magnetic field (active regions) in the outer layer... more Abstract The spatial configuration of enhanced magnetic field (active regions) in the outer layers of the Sun derives from the interaction between convective flows and solar magnetic field. Temporal evolution of active regions is considered the main responsible of radiative output variations. Particularly, solar irradiance variations are explained in terms of temporal and spatial evolution of solar surface magnetic fields.
Abstract. We investigate the spatial distribution of reticular clusters of magnetic features on t... more Abstract. We investigate the spatial distribution of reticular clusters of magnetic features on the solar surface. For this purpose, we develop a void searching algorithm, such as those used in cosmology to study galaxy spatial distributions. We apply this method to a temporal series of large FoV MDI (Michelson Doppler Imager) magnetograms, to identify voids between magnetic structures and to extract their normalized Void Probability Function, which characterizes the scale distribution of magnetic inter-cluster voids.
Abstract We present a comparative study of photometric and dynamic properties of photospheric bri... more Abstract We present a comparative study of photometric and dynamic properties of photospheric bright points (BPs) observed at the disk centre in the active region (AR) NOAA 10912 and in the quiet Sun. We found that the average concentration of BPs is 54% larger in the AR than in the quiet Sun. We also measure a decrease of the BP concentration and an increase of their size moving away from the AR centre.
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Papers by Dario Del Moro