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139 results on '"Telloni, D."'

107. Turbulence in the heliosphere.

Author

Adhikari, L., Zank, G. P., Hunana, P., Bruno, R., Telloni, D., and Marino, R.

Subjects
TURBULENCE, HELIOSPHERE, SOLAR wind, SCIENTIFIC observation, STEADY-state theory (Cosmology), TRANSPORT theory
Abstract

Turbulence in the solar wind is ubiquitous. To understand the transport of low-frequency turbulence in the sub- and super-Alfvénic solar wind flow, Zank et al. 2012 developed an extensive turbulence transport model that describes the evolution of the energy in forward and backward propagating modes, the total turbulent energy, the cross-helicity, the residual energy, the correlation lengths corresponding to forward and backward propagating modes, and the correlation length of the residual energy. Adhikari et. al. 2015 presented the first detailed solution of Zank et al., and found good agreement between the Zank et al. model and observations. Here, we solve the 1D steady-state turbulence transport equations with and without sources of turbulence, and show that all the identified sources are required to reproduce the theoretical results to be consistent with the observations. [ABSTRACT FROM AUTHOR]

Published
2016
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113. METIS: the visible and UV coronagraph for solar orbiter

Author

Sodnik, Zoran, Karafolas, Nikos, Cugny, Bruno, Romoli, M., Landini, F., Antonucci, E., Andretta, V., Berlicki, A., Fineschi, S., Moses, J. D., Naletto, G., Nicolosi, P., Nicolini, G., Spadaro, D., Teriaca, L., Baccani, C., Focardi, M., Pancrazzi, M., Pucci, S., Abbo, L., Bemporad, A., Capobianco, G., Massone, G., Telloni, D., Magli, E., Da Deppo, V., Frassetto, F., Pelizzo, M. G., Poletto, L., Uslenghi, M., Vives, S., and Malvezzi, M.

Published
2017
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133. Connecting Solar Orbiter remote-sensing observations and Parker Solar Probe in situ measurements with a numerical MHD reconstruction of the Parker spiral

Author

Ruggero Biondo, Alessandro Bemporad, Paolo Pagano, Daniele Telloni, Fabio Reale, Marco Romoli, Vincenzo Andretta, Ester Antonucci, Vania Da Deppo, Yara De Leo, Silvano Fineschi, Petr Heinzel, Daniel Moses, Giampiero Naletto, Gianalfredo Nicolini, Daniele Spadaro, Marco Stangalini, Luca Teriaca, Federico Landini, Clementina Sasso, Roberto Susino, Giovanna Jerse, Michela Uslenghi, Maurizio Pancrazzi, Biondo R., Bemporad A., Pagano P., Telloni D., Reale F., Romoli M., Andretta V., Antonucci E., Da Deppo V., De Leo Y., Fineschi S., Heinzel P., Moses D., Naletto G., Nicolini G., Spadaro D., Stangalini M., Teriaca L., Landini F., Sasso C., Susino R., Jerse G., Uslenghi M., and Pancrazzi M.

Subjects
Plasma Physics (physics.plasm-ph), Settore FIS/05 - Astronomia E Astrofisica, Astrophysics - Solar and Stellar Astrophysics, Physics - Space Physics, Space and Planetary Science, FOS: Physical sciences, Astronomy and Astrophysics, magnetohydrodynamics (MHD) – methods: numerical – solar wind – Sun: heliosphere – Sun: corona, magnetohydrodynamics(MHD),methods:numerical,solar wind,Sun:heliosphere,Sun:corona, Physics - Plasma Physics, Solar and Stellar Astrophysics (astro-ph.SR), Space Physics (physics.space-ph)
Abstract

As a key feature, NASA's Parker Solar Probe (PSP) and ESA-NASA's Solar Orbiter (SO) missions cooperate to trace solar wind and transients from their sources on the Sun to the inner interplanetary space. The goal of this work is to accurately reconstruct the interplanetary Parker spiral and the connection between coronal features observed remotely by the Metis coronagraph on-board SO and those detected in situ by PSP at the time of the first PSP-SO quadrature of January 2021. We use the Reverse In-situ and MHD Approach (RIMAP), a hybrid analytical-numerical method performing data-driven reconstructions of the Parker spiral. RIMAP solves the MHD equations on the equatorial plane with the PLUTO code, using the measurements collected by PSP between 0.1 and 0.2 AU as boundary conditions. Our reconstruction connects density and wind speed measurements provided by Metis (3-6 solar radii) to those acquired by PSP (21.5 solar radii) along a single streamline. The capability of our MHD model to connect the inner corona observed by Metis and the super Alfv\'enic wind measured by PSP, not only confirms the research pathways provided by multi-spacecraft observations, but also the validity and accuracy of RIMAP reconstructions as a possible test bench to verify models of transient phenomena propagating across the heliosphere, such as coronal mass ejections, solar energetic particles and solar wind switchbacks., Comment: Astronomy & Astrophysics, Solar Orbiter First Results (Nominal Mission Phase), (in press) DOI: 10.1051/0004-6361/202244535

Published
2022

135. Linking Small-scale Solar Wind Properties with Large-scale Coronal Source Regions through Joint Parker Solar Probe–Metis/Solar Orbiter Observations

Author

Daniele Telloni, Gary P. Zank, Luca Sorriso-Valvo, Raffaella D’Amicis, Olga Panasenco, Roberto Susino, Roberto Bruno, Denise Perrone, Laxman Adhikari, Haoming Liang, Masaru Nakanotani, Lingling Zhao, Lina Z. Hadid, Beatriz Sánchez-Cano, Daniel Verscharen, Marco Velli, Catia Grimani, Raffaele Marino, Francesco Carbone, Salvatore Mancuso, Ruggero Biondo, Paolo Pagano, Fabio Reale, Stuart D. Bale, Justin C. Kasper, Anthony W. Case, Thierry Dudok de Wit, Keith Goetz, Peter R. Harvey, Kelly E. Korreck, Davin Larson, Roberto Livi, Robert J. MacDowall, David M. Malaspina, Marc Pulupa, Michael L. Stevens, Phyllis Whittlesey, Marco Romoli, Vincenzo Andretta, Vania Da Deppo, Silvano Fineschi, Petr Heinzel, John D. Moses, Giampiero Naletto, Gianalfredo Nicolini, Daniele Spadaro, Marco Stangalini, Luca Teriaca, Gerardo Capobianco, Giuseppe E. Capuano, Chiara Casini, Marta Casti, Paolo Chioetto, Alain J. Corso, Yara De Leo, Michele Fabi, Federica Frassati, Fabio Frassetto, Silvio Giordano, Salvo L. Guglielmino, Giovanna Jerse, Federico Landini, Alessandro Liberatore, Enrico Magli, Giuseppe Massone, Mauro Messerotti, Maurizio Pancrazzi, Maria G. Pelizzo, Paolo Romano, Clementina Sasso, Udo Schühle, Alessandra Slemer, Thomas Straus, Michela Uslenghi, Cosimo A. Volpicelli, Luca Zangrilli, Paola Zuppella, Lucia Abbo, Frédéric Auchère, Regina Aznar Cuadrado, Arkadiusz Berlicki, Angela Ciaravella, Philippe Lamy, Alessandro Lanzafame, Marco Malvezzi, Piergiorgio Nicolosi, Giuseppe Nisticò, Hardi Peter, Sami K. Solanki, Leonard Strachan, Kanaris Tsinganos, Rita Ventura, Jean-Claude Vial, Joachim Woch, Gaetano Zimbardo, Telloni D., Zank G.P., Sorriso-Valvo L., D'amicis R., Panasenco O., Susino R., Bruno R., Perrone D., Adhikari L., Liang H., Nakanotani M., Zhao L., Hadid L.Z., Sanchez-Cano B., Verscharen D., Velli M., Grimani C., Marino R., Carbone F., Mancuso S., Biondo R., Pagano P., Reale F., Bale S.D., Kasper J.C., Case A.W., De Wit T.D., Goetz K., Harvey P.R., Korreck K.E., Larson D., Livi R., Macdowall R.J., Malaspina D.M., Pulupa M., Stevens M.L., Whittlesey P., Romoli M., Andretta V., Deppo V.D., Fineschi S., Heinzel P., Moses J.D., Naletto G., Nicolini G., Spadaro D., Stangalini M., Teriaca L., Capobianco G., Capuano G.E., Casini C., Casti M., Chioetto P., Corso A.J., Leo Y.D., Fabi M., Frassati F., Frassetto F., Giordano S., Guglielmino S.L., Jerse G., Landini F., Liberatore A., Magli E., Massone G., Messerotti M., Pancrazzi M., Pelizzo M.G., Romano P., Sasso C., Schuhle U., Slemer A., Straus T., Uslenghi M., Volpicelli C.A., Zangrilli L., Zuppella P., Abbo L., Auchere F., Cuadrado R.A., Berlicki A., Ciaravella A., Lamy P., Lanzafame A., Malvezzi M., Nicolosi P., Nistico G., Peter H., Solanki S.K., Strachan L., Tsinganos K., Ventura R., Vial J.-C., Woch J., and Zimbardo G.

Subjects
Magnetohydrodynamics (694), Settore FIS/05 - Astronomia E Astrofisica, Astronomi, astrofysik och kosmologi, Space and Planetary Science, Solar corona (1483), Space plasmas (1544), Solar wind (1534), Interplanetary turbulence (830), Astronomy, Astrophysics and Cosmology, Astronomy and Astrophysics, Alfven waves (23), Heliosphere (711)
Abstract

The solar wind measured in situ by Parker Solar Probe in the very inner heliosphere is studied in combination with the remote-sensing observation of the coronal source region provided by the METIS coronagraph aboard Solar Orbiter. The coronal outflows observed near the ecliptic by Metis on 2021 January 17 at 16:30 UT, between 3.5 and 6.3 R ⊙ above the eastern solar limb, can be associated with the streams sampled by PSP at 0.11 and 0.26 au from the Sun, in two time intervals almost 5 days apart. The two plasma flows come from two distinct source regions, characterized by different magnetic field polarity and intensity at the coronal base. It follows that both the global and local properties of the two streams are different. Specifically, the solar wind emanating from the stronger magnetic field region has a lower bulk flux density, as expected, and is in a state of well-developed Alfvénic turbulence, with low intermittency. This is interpreted in terms of slab turbulence in the context of nearly incompressible magnetohydrodynamics. Conversely, the highly intermittent and poorly developed turbulent behavior of the solar wind from the weaker magnetic field region is presumably due to large magnetic deflections most likely attributed to the presence of switchbacks of interchange reconnection origin.

Published
2022

136. 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

137. 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

138. Local dimensionality and inverse persistence analysis of atmospheric turbulence in the stable boundary layer.

Author

Carbone F, Alberti T, Faranda D, Telloni D, Consolini G, and Sorriso-Valvo L

Subjects
Anisotropy, Fractals, Systems Theory
Abstract

The dynamics across different scales in the stable atmospheric boundary layer has been investigated by means of two metrics, based on instantaneous fractal dimensions and grounded in dynamical systems theory. The wind velocity fluctuations obtained from data collected during the Cooperative Atmosphere-Surface Exchange Study-1999 experiment were analyzed to provide a local (in terms of scales) and an instantaneous (in terms of time) description of the fractal properties and predictability of the system. By analyzing the phase-space projections of the continuous turbulent, intermittent, and radiative regimes, a progressive transformation, characterized by the emergence of multiple low-dimensional clusters embedded in a high-dimensional shell and a two-lobe mirror symmetrical structure of the inverse persistence, have been found. The phase space becomes increasingly complex and anisotropic as the turbulent fluctuations become uncorrelated. The phase space is characterized by a three-dimensional structure for the continuous turbulent samples in a range of scales compatible with the inertial subrange, where the phase-space-filling turbulent fluctuations dominate the dynamics, and is low dimensional in the other regimes. Moreover, lower-dimensional structures present a stronger persistence than the higher-dimensional structures. Eventually, all samples recover a three-dimensional structure and higher persistence level at large scales, far from the inertial subrange. The two metrics obtained in the analysis can be considered as proxies for the decorrelation time and the local anisotropy in the turbulent flow.

Published
2022
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139. Transition to turbulence in a five-mode Galerkin truncation of two-dimensional magnetohydrodynamics.

Author

Carbone F, Telloni D, Zank G, and Sorriso-Valvo L

Abstract

The chaotic dynamics of a low-order Galerkin truncation of the two-dimensional magnetohydrodynamic system, which reproduces the dynamics of fluctuations described by nearly incompressible magnetohydrodynamic in the plane perpendicular to a background magnetic field, is investigated by increasing the external forcing terms. Although this is the case closest to two-dimensional hydrodynamics, which shares some aspects with the classical Feigenbaum scenario of transition to chaos, the presence of magnetic fluctuations yields a very complex interesting route to chaos, characterized by the splitting into multiharmonic structures of the field amplitudes, and a mixing of phase-locking and free phase precession acting intermittently. When the background magnetic field lies in the plane, the system supports the presence of Alfvén waves thus lowering the nonlinear interactions. Interestingly enough, the dynamics critically depends on the angle between the direction of the magnetic field and the reference system of the wave vectors. Above a certain critical angle, independently from the external forcing, a breakdown of the phase locking appears, accompanied with a suppression of the chaotic dynamics, replaced by a simple periodic motion.

Published
2021
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