Search

Your search keyword '"Y. De Leo"' showing total 8 results
Start Over Author "Y. De Leo"
Sorry, I don't understand your search. ×
8 results on '"Y. De Leo"'

1. Slow wind belt in the quiet solar corona

Author

E. Antonucci, C. Downs, G. E. Capuano, D. Spadaro, R. Susino, D. Telloni, V. Andretta, V. Da Deppo, Y. De Leo, S. Fineschi, F. Frassetto, F. Landini, G. Naletto, G. Nicolini, M. Pancrazzi, M. Romoli, M. Stangalini, L. Teriaca, and M. Uslenghi

Subjects
Astrophysics - Solar and Stellar Astrophysics, Physics - Space Physics, FOS: Physical sciences, Condensed Matter Physics, Solar and Stellar Astrophysics (astro-ph.SR), Space Physics (physics.space-ph)
Abstract

The slow solar wind belt in the quiet corona, observed with the Metis coronagraph on board Solar Orbiter on May 15, 2020, during the activity minimum of the cycle 24, in a field of view extending from 3.8 [Formula: see text] to 7.0 [Formula: see text], is formed by a slow and dense wind stream running along the coronal current sheet, accelerating in the radial direction and reaching at 6.8 [Formula: see text] a speed within 150 and 190 km s−1, depending on the assumptions on the velocity distribution of the neutral hydrogen atoms in the coronal plasma. The slow stream is separated by thin regions of high velocity shear from faster streams, almost symmetric relative to the current sheet, with peak velocity within 175 and 230 km s−1 at the same coronal level. The density–velocity structure of the slow wind zone is discussed in terms of the expansion factor of the open magnetic field lines that is known to be related to the speed of the quasi-steady solar wind, and in relation to the presence of a web of quasi-separatrix layers, S-web, the potential sites of reconnection that release coronal plasma into the wind. The parameters characterizing the coronal magnetic field lines are derived from 3D MHD model calculations. The S-web is found to coincide with the latitudinal region where the slow wind is observed in the outer corona and is surrounded by thin layers of open field lines expanding in a non-monotonic way.

Published
2023

2. First polar observations of the fast solar wind with the Metis - Solar Orbiter coronagraph : Role of 2D turbulence energy dissipation in the wind acceleration

Author

D. Telloni, E. Antonucci, L. Adhikari, G. P. Zank, S. Giordano, M. Vai, L.-L. Zhao, V. Andretta, A. Burtovoi, G. E. Capuano, V. Da Deppo, Y. De Leo, S. Fineschi, C. Grimani, P. Heinzel, G. Jerse, F. Landini, A. Liberatore, J. D. Moses, G. Naletto, G. Nicolini, M. Pancrazzi, M. Romoli, G. Russano, C. Sasso, A. Slemer, D. Spadaro, M. Stangalini, R. Susino, L. Teriaca, M. Uslenghi, L. Sorriso-Valvo, R. Marino, D. Perrone, R. D’Amicis, and R. Bruno

Subjects
UV radiation [Sun], corona [Sun], solar wind, Astronomi, astrofysik och kosmologi, Space and Planetary Science, Astronomy, Astrophysics and Cosmology, Astronomy and Astrophysics, magnetohydrodynamics (MHD)
Abstract

Context.The fast solar wind is known to emanate from polar coronal holes.Aims.This Letter reports the first estimate of the expansion rate of polar coronal flows performed by the Metis coronagraph on board Solar Orbiter.Methods.By exploiting simultaneous measurements in polarized white light and ultraviolet intensity of the neutral hydrogen Lyman-αline, it was possible to extend observations of the outflow velocity of the main component of the solar wind from polar coronal holes out to 5.5 R⊙, the limit of diagnostic applicability and observational capabilities.Results.We complement the results obtained with analogous polar observations performed with the UltraViolet Coronagraph Spectrometer on board the SOlar and Heliospheric Observatory during the previous full solar activity cycle, and find them to be satisfactorily reproduced by a magnetohydrodynamic turbulence model.Conclusions.This suggests that the dissipation of 2D turbulence energy is a viable mechanism for coronal plasma heating and the subsequent acceleration of the fast solar wind.

Published
2023

3. First-light Science Observations of the Metis Solar Coronagraph

Author

Marco Romoli, Gerardo Capobianco, F. Frassetto, M. Casti, M. Fabi, Vincenzo Andretta, Silvano Fineschi, Y. De Leo, V. Da Deppo, and Alessandro Bemporad

Subjects
Physics, business.industry, Ecliptic, Polarimeter, First light, Corona, law.invention, Telescope, Solar wind, Orbiter, Optics, law, business, Coronagraph
Abstract

Metis coronagraph is one of the remote-sensing instruments of the Solar Orbiter mission launched in February 2020. The mission profile will allow for the first time the remote-sensing observation of the Sun from as close as 0.28 AU and from ecliptic latitudes as high as 30?. Metis, in particular, is aimed at the study and the overall characterization of the solar corona and solar wind. This instrument is an innovative inverted-occultation coronagraph that will image the solar corona for the first time simultaneously in two different wavelength band-passes: in the linearly-polarized visible-light (VL), between 580 and 640 nm, and in the ultraviolet (UV) Lyman-a line of hydrogen, HI at 121.6 nm by combining in the same telescope UV interference mirror coatings (Al/MgF2) and spectral bandpass filters. The visible channel includes a broad-band polarimeter to observe the linearly polarized component of the K corona. These measurements will allow a complete characterization of the physical parameters, such as density and outflow speed, of the two major plasma components of the corona and the solar wind: electrons (protons) and hydrogen. After a period of commissioning, by the summer of 2020, Metis will have performed the First-light Science Observations during the “Remote-Sensing Check-out Window” (RSCW) that is a telemetry contact period, specifically allocated before entering the operational phase at the end of 2021. This presentation will report the first-light science observations of Metis represented by the UV and polarized VL images of the corona. The calibration results from the commissioning will be used for the correction of the instrumental effects. The resulting first-light maps of the coronal electron and hydrogen distributions will be presented.

Published
2021
Full Text
View/download PDF

4. The first coronal mass ejection observed in both visible-light and UV HI Ly-α channels of the Metis coronagraph on board Solar Orbiter

Author

V. Andretta, A. Bemporad, Y. De Leo, G. Jerse, F. Landini, M. Mierla, G. Naletto, M. Romoli, C. Sasso, A. Slemer, D. Spadaro, R. Susino, D.-C. Talpeanu, D. Telloni, L. Teriaca, M. Uslenghi, E. Antonucci, F. Auchère, D. Berghmans, A. Berlicki, G. Capobianco, G. E. Capuano, C. Casini, M. Casti, P. Chioetto, V. Da Deppo, M. Fabi, S. Fineschi, F. Frassati, F. Frassetto, S. Giordano, C. Grimani, P. Heinzel, A. Liberatore, E. Magli, G. Massone, M. Messerotti, D. Moses, G. Nicolini, M. Pancrazzi, M.-G. Pelizzo, P. Romano, U. Schühle, M. Stangalini, Th. Straus, C. A. Volpicelli, L. Zangrilli, P. Zuppella, L. Abbo, R. Aznar Cuadrado, R. Bruno, A. Ciaravella, R. D’Amicis, P. Lamy, A. Lanzafame, A. M. Malvezzi, P. Nicolosi, G. Nisticò, H. Peter, C. Plainaki, L. Poletto, F. Reale, S. K. Solanki, L. Strachan, G. Tondello, K. Tsinganos, M. Velli, R. Ventura, J.-C. Vial, J. Woch, G. Zimbardo, Andretta V., Bemporad A., De Leo Y., Jerse G., Landini F., Mierla M., Naletto G., Romoli M., Sasso C., Slemer A., Spadaro D., Susino R., Talpeanu D.-C., Telloni D., Teriaca L., Uslenghi M., Antonucci E., Auchere F., Berghmans D., Berlicki A., Capobianco G., Capuano G.E., Casini C., Casti M., Chioetto P., Da Deppo V., Fabi M., Fineschi S., Frassati F., Frassetto F., Giordano S., Grimani C., Heinzel P., Liberatore A., Magli E., Massone G., Messerotti M., Moses D., Nicolini G., Pancrazzi M., Pelizzo M.-G., Romano P., Schuhle U., Stangalini M., Straus T., Volpicelli C.A., Zangrilli L., Zuppella P., Abbo L., Aznar Cuadrado R., Bruno R., Ciaravella A., D'amicis R., Lamy P., Lanzafame A., Malvezzi A.M., Nicolosi P., Nistico G., Peter H., Plainaki C., Poletto L., Reale F., Solanki S.K., Strachan L., Tondello G., Tsinganos K., Velli M., Ventura R., Vial J.-C., Woch J., Zimbardo G., INAF - Osservatorio Astronomico di Capodimonte (OAC), Istituto Nazionale di Astrofisica (INAF), INAF - Osservatorio Astrofisico di Torino (OATo), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Dipartamento di Fisica e Astronomia 'Ettore Majorana', Università degli studi di Catania [Catania], INAF - Osservatorio Astronomico di Trieste (OAT), Royal Observatory of Belgium [Brussels] (ROB), Institute of Geodynamics of the Romanian Academy, Romanian Academy, Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Dipartimento di Fisica e Astronomia [Firenze], Università degli Studi di Firenze = University of Florence [Firenze] (UNIFI), INAF - Osservatorio Astrofisico di Catania (OACT), Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Istituto di Astrofisica Spaziale e Fisica Cosmica - Milano (IASF-MI), Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Astronomical Institute [Wroclaw], University of Wrocław [Poland] (UWr), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Dipartimento di Scienze Pure et Applicate (DiSPea), Università degli Studi di Urbino 'Carlo Bo', Istituto Nazionale di Fisica Nucleare, Sezione di Firenze (INFN, Sezione di Firenze), Istituto Nazionale di Fisica Nucleare (INFN), Astronomical Institute of the Czech Academy of Sciences (ASU / CAS), Czech Academy of Sciences [Prague] (CAS), Università degli studi di Torino (UNITO), Dipartimento di Elettronica e Telecomunicazioni [Torino] (DET), Politecnico di Torino = Polytechnic of Turin (Polito), NASA Headquarters, Istituto di Elettronica e di Ingegneria dell'Informazione e delle Telecomunicazioni (IEIIT), Consiglio Nazionale delle Ricerche (CNR), Agenzia Spaziale Italiana (ASI), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), INAF - Osservatorio Astronomico di Palermo (OAPa), HELIOS - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Università di Pavia, Dipartimento di Fisica [Arcavacata di Rende], Università della Calabria [Arcavacata di Rende] (Unical), Dipartimento di Fisica e Chimica 'Emilio Segrè' (DiFC), Università degli studi di Palermo - University of Palermo, Naval Research Laboratory (NRL), Department of Physics [Athens], National and Kapodistrian University of Athens (NKUA), University of California [Los Angeles] (UCLA), and University of California

Subjects
Physics, 010504 meteorology & atmospheric sciences, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Sun: corona, Sun: coronal mass ejections (CMEs), Astronomy and Astrophysics, Astrophysics, Alpha (navigation), Sun: UV radiation, 01 natural sciences, law.invention, On board, Orbiter, Space and Planetary Science, law, 0103 physical sciences, Coronal mass ejection, Metis, 010303 astronomy & astrophysics, Coronagraph, Sun: atmosphere, 0105 earth and related environmental sciences, Visible spectrum, Sun: atmosphere – Sun: corona – Sun: UV radiation – Sun: coronal mass ejections (CMEs)
Abstract

Context.The Metis coronagraph on board Solar Orbiter offers a new view of coronal mass ejections (CMEs), observing them for the first time with simultaneous images acquired with a broad-band filter in the visible-light interval and with a narrow-band filter around the H ILy-αline at 121.567 nm, the so-called Metis UV channel.Aims.We show the first Metis observations of a CME, obtained on 16 and 17 January 2021. The event was also observed by the EUI/FSI imager on board Solar Orbiter, as well as by other space-based coronagraphs, such as STEREO-A/COR2 and SOHO/LASCO/C2, whose images are combined here with Metis data.Methods.Different images are analysed here to reconstruct the 3D orientation of the expanding CME flux rope using the graduated cylindrical shell model. This also allows us to identify the possible location of the source region. Measurements of the CME kinematics allow us to quantify the expected Doppler dimming in the Ly-αchannel.Results.Observations show that most CME features seen in the visible-light images are also seen in the Ly-αimages, although some features in the latter channel appear more structured than their visible-light counterparts. We estimated the expansion velocity of this event to be below 140 km s−1. Hence, these observations can be understood by assuming that Doppler dimming effects do not strongly reduce the Ly-αemission from the CME. These velocities are comparable with or smaller than the radial velocities inferred from the same data in a similar coronal structure on the east side of the Sun.Conclusions.The first observations by Metis of a CME demonstrate the capability of the instrument to provide valuable and novel information on the structure and dynamics of these coronal events. Considering also its diagnostics capabilities regarding the conditions of the ambient corona, Metis promises to significantly advance our knowledge of such phenomena.

Published
2021
Full Text
View/download PDF

5. In-flight calibration of Metis coronagraph on board of Solar Orbiter

Author

K. Heerlein, Catia Grimani, F. Frassetto, Michela Uslenghi, Federico Landini, G. Jerse, Vincenzo Andretta, Y. De Leo, Luca Teriaca, Gianalfredo Nicolini, M. G. Pelizzo, Daniele Spadaro, Enrico Magli, Gerardo Capobianco, Roberto Susino, P. Heinzel, Maurizio Pancrazzi, C.A. Volpicelli, Clementina Sasso, Alessandro Liberatore, Alessandra Slemer, M. Casti, Giampiero Naletto, V. Da Deppo, P. Zuppella, Marco Romoli, M. Fabi, Thomas Straus, Alessandro Bemporad, P. Romano, and Silvano Fineschi

Subjects
Physics, Vignetting, Linear polarization, business.industry, Liquid crystal variable retarder, Ecliptic, Metis, Sun, Polarimeter, Solar corona, law.invention, Coronagraph, Solar wind, Orbiter, Optics, law, Polarization, Solar Orbiter, business
Abstract

Metis coronagraph is one of the remote-sensing instruments of the Solar Orbiter mission launched at the begin of 2020. The mission profile will allow for the first time the remote-sensing observation of the Sun from a very close distance and increasing the latitude with respect to the ecliptic plane. In particular, Metis is aimed at the overall characterization and study of the solar corona and solar wind. Metis instrument acquires images of the solar corona in two different wavelengths simultaneously; ultraviolet (UV) and visible-light (VL). The VL channel includes a polarimeter with an electro-optically modulating Liquid Crystal Variable Retarder (LCVR) to measure the linearly polarized brighness pB) of the K-corona. This paper presents part of the in-flight calibration results for both wavelength channels together with a comparison with on-ground calibrations. The orientation of the K-corona linear polarization was used for the in-flight calibration of the Metis polarimeter. This paper describes the correction of the on-ground VL vignetting function after the in-flight adjustment of the internal occulter. The same vignetting function was adaptated to the UV channel.

Published
2021

6. On-ground flat-field calibration of the Metis coronagraph onboard the Solar Orbiter ESA mission

Author

Enrico Magli, M. Casti, Marco Romoli, Daniele Spadaro, Chiara Casini, M. G. Pelizzo, M. Fabi, Y. De Leo, F. Frassetto, Alessandro Bemporad, Roberto Susino, Silvano Fineschi, Federico Landini, V. Da Deppo, Catia Grimani, Michela Uslenghi, Luca Teriaca, K. Heerlein, G. Jerse, Marco Stangalini, P. Heinzel, Giampiero Naletto, P. Chioetto, V. Andretta, P. Zuppella, Clementina Sasso, F. Frassati, T. Straus, Alessandro Liberatore, Maurizio Pancrazzi, P. Romano, G. Nicolini, Alessandra Slemer, and Antonio Volpicelli

Subjects
Flat Field, Metis, Space Instrumentation, law.invention, Coronagraph, Orbiter, law, Solar Orbiter, Environmental science, Field calibration, Remote sensing
Published
2021

7. First light observations of the solar wind in the outer corona with the Metis coronagraph

Author

F. Reale, Giuseppe Tondello, Daniele Telloni, P. Zuppella, Jean-Claude Vial, D. Moses, Luca Teriaca, Giampiero Naletto, Marco Romoli, Petr Heinzel, Federico Landini, Piergiorgio Nicolosi, Udo Schühle, Michela Uslenghi, Maurizio Pancrazzi, Silvano Fineschi, Rita Ventura, Leonard Strachan, Raffaella D'Amicis, Alessandro Liberatore, Christina Plainaki, Mauro Messerotti, Enrico Magli, Marco Stangalini, C.A. Volpicelli, Roberto Bruno, Alessandro Bemporad, Giuseppe Massone, F. Frassetto, R. Aznar Cuadrado, A. Berlicki, F. Auchere, Paolo Romano, G. Capuano, A. M. Malvezzi, Silvio Giordano, Y. De Leo, V. Da Deppo, T. Straus, Kanaris Tsinganos, Alessandra Slemer, Sami K. Solanki, Hardi Peter, V. Andretta, Cooper Downs, Daniele Spadaro, Gerardo Capobianco, A. C. Lanzafame, Gianalfredo Nicolini, Roberto Susino, Clementina Sasso, L. Zangrilli, Marco Velli, M. Casti, E. Antonucci, Angela Ciaravella, Giuseppe Nisticò, Catia Grimani, Lucia Abbo, G. Jerse, M. Fabi, Federica Frassati, Luca Poletto, Philippe Lamy, Y. M. Wang, Joachim Woch, M. G. Pelizzo, G. Zimbardo, Università degli Studi di Firenze = University of Florence [Firenze] (UNIFI), Istituto Nazionale di Astrofisica (INAF), INAF - Osservatorio Astronomico di Capodimonte (OAC), Università degli studi di Catania [Catania], INAF - Osservatorio Astrofisico di Catania (OACT), CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Predictive Sciences Inc., INAF - Osservatorio Astrofisico di Torino (OATo), Astronomical Institute of the Czech Academy of Sciences (ASU / CAS), Czech Academy of Sciences [Prague] (CAS), Università degli studi di Torino (UNITO), Universita degli Studi di Padova, Istituto di Astrofisica Spaziale e Fisica Cosmica - Milano (IASF-MI), Naval Research Laboratory (NRL), Catholic University of America, Università degli Studi di Urbino 'Carlo Bo', Università degli studi di Trieste, Politecnico di Torino = Polytechnic of Turin (Polito), NASA Headquarters, Institute of Electronics, Computer and Telecommunication Engineering (IEIIT-CNR), Politecnico di Torino = Polytechnic of Turin (Polito)-Consiglio Nazionale delle Ricerche [Torino] (CNR), Agenzia Spaziale Italiana (ASI), Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Astronomical Institute [Wroclaw], University of Wrocław [Poland] (UWr), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), INAF - Osservatorio Astronomico di Palermo (OAPa), HELIOS - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Università di Pavia, Università della Calabria [Arcavacata di Rende] (Unical), Università degli studi di Palermo - University of Palermo, National and Kapodistrian University of Athens (NKUA), University of California [Los Angeles] (UCLA), University of California, Romoli M., Antonucci E., Andretta V., Capuano G.E., Da Deppo V., De Leo Y., Downs C., Fineschi S., Heinzel P., Landini F., Liberatore A., Naletto G., Nicolini G., Pancrazzi M., Sasso C., Spadaro D., Susino R., Telloni D., Teriaca L., Uslenghi M., Wang Y.-M., Bemporad A., Capobianco G., Casti M., Fabi M., Frassati F., Frassetto F., Giordano S., Grimani C., Jerse G., Magli E., Massone G., Messerotti M., Moses D., Pelizzo M.-G., Romano P., Schuhle U., Slemer A., Stangalini M., Straus T., Volpicelli C.A., Zangrilli L., Zuppella P., Abbo L., Auchere F., Aznar Cuadrado R., Berlicki A., Bruno R., Ciaravella A., D'amicis R., Lamy P., Lanzafame A., Malvezzi A.M., Nicolosi P., Nistico G., Peter H., Plainaki C., Poletto L., Reale F., Solanki S.K., Strachan L., Tondello G., Tsinganos K., Velli M., Ventura R., Vial J.-C., Woch J., and Zimbardo G.

Subjects
010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, Solar wind, FOS: Physical sciences, Astrophysics, 01 natural sciences, Wind speed, law.invention, symbols.namesake, Sun: corona – solar wind – Sun: UV radiation, law, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Coronagraph, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Physics, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Sun: corona, Astronomy and Astrophysics, Plasma, Solar wind, Sun: corona, Sun: UV radiation, Sun: UV radiation, Corona, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Temporal resolution, Physics::Space Physics, symbols, Outflow, Doppler effect
Abstract

In this work, we present an investigation of the wind in the solar corona that has been initiated by observations of the resonantly scattered ultraviolet emission of the coronal plasma obtained with UVCS-SOHO, designed to measure the wind outflow speed by applying Doppler dimming diagnostics. Metis on Solar Orbiter complements the UVCS spectroscopic observations that were performed during solar activity cycle 23 by simultaneously imaging the polarized visible light and the H I Lyman-α corona in order to obtain high spatial and temporal resolution maps of the outward velocity of the continuously expanding solar atmosphere. The Metis observations, taken on May 15, 2020, provide the first H I Lyman-α images of the extended corona and the first instantaneous map of the speed of the coronal plasma outflows during the minimum of solar activity and allow us to identify the layer where the slow wind flow is observed. The polarized visible light (580–640 nm) and the ultraviolet H I Lyα (121.6 nm) coronal emissions, obtained with the two Metis channels, were combined in order to measure the dimming of the UV emission relative to a static corona. This effect is caused by the outward motion of the coronal plasma along the direction of incidence of the chromospheric photons on the coronal neutral hydrogen. The plasma outflow velocity was then derived as a function of the measured Doppler dimming. The static corona UV emission was simulated on the basis of the plasma electron density inferred from the polarized visible light. This study leads to the identification, in the velocity maps of the solar corona, of the high-density layer about ±10° wide, centered on the extension of a quiet equatorial streamer present at the east limb – the coronal origin of the heliospheric current sheet – where the slowest wind flows at about 160 ± 18 km s−1 from 4 R⊙ to 6 R⊙. Beyond the boundaries of the high-density layer, the wind velocity rapidly increases, marking the transition between slow and fast wind in the corona.

Published
2021
Full Text
View/download PDF

8. Measuring the F-corona intensity through time correlation of total and polarized visible light images

Author

A. Burtovoi, G. Naletto, S. Dolei, D. Spadaro, M. Romoli, F. Landini, and Y. De Leo

Subjects
Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Physics::Space Physics, FOS: Physical sciences, Astrophysics::Solar and Stellar Astrophysics, Astronomy and Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract

We present a new correlation method for deriving the F-corona intensity distribution, which is based on the analysis of the evolution of the total and polarized visible light (VL) images. We studied the one-month variation profiles of the total and polarized brightness acquired with Large Angle Spectrometric COronagraph (LASCO-C2) and found that in some regions they are highly correlated. Assuming that the F-corona does not vary significantly on a timescale of one month, we estimated its intensity in the high-correlation regions and reconstructed the corresponding intensity maps both during the solar-minimum and solar-maximum periods. Systematic uncertainties were estimated by performing dedicated simulations. We compared the resulting F-corona images with those determined using the inversion technique and found that the correlation method provides a smoother intensity distribution. We also obtained that the F-corona images calculated for consecutive months show no significant variation. Finally, we note that this method can be applied to the future high-cadence VL observations carried out with the Metis/Solar Orbiter coronagraph., 16 pages, 21 figures

Published
2022
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results