Nature of the Energy Source Powering Solar Coronal Loops Driven by Nanoflares? L
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Fundamentals of Impulsive Energy Release in the Corona Heliophysics 2050 Workshop White Paper A
Heliophysics 2050 White Papers (2021) 4093.pdf Fundamentals of impulsive energy release in the corona Heliophysics 2050 Workshop white paper A. Y. Shih (NASA Goddard Space Flight Center), L. Glesener (UMN), S. Krucker (UCB), S. Guidoni (Amer. Univ.), S. Christe (GSFC), K. Reeves (SAO), S. Gburek (PAS), A. Caspi (SwRI), M. Alaoui (GSFC/CUA), J. Allred (GSFC), M. Battaglia (FHNW), W. Baumgartner (MSFC), B. Dennis (GSFC), J. Drake (UMD), K. Goetz (UMN), L. Golub (SAO), I. Hannah (Univ. of Glasgow), L. Hayes (GSFC/USRA), G. Holman (GSFC/Emeritus), A. Inglis (GSFC/CUA), J. Ireland (GSFC), G. Kerr (GSFC/CUA), J. Klimchuk (GSFC), D. McKenzie (MSFC), C. Moore (SAO), S. Musset (Univ. of Glasgow), J. Reep (NRL), D. Ryan (GSFC/AU), P. Saint-Hilaire (UCB), S. Savage (MSFC), R. Schwartz (GSFC/AU), D. Seaton (NOAA), M. Stęślicki (PAS), T. Woods (LASP) Introduction Solar eruptive events are the most energetic and geo-effective space-weather drivers. They originate in the corona near the Sun’s surface as a combination of solar flares (impulsive bursts of radiation across the entire electromagnetic spectrum) and coronal mass ejections (CMEs; expulsions of magnetized plasma into interplanetary space). The radiation and energetic particles they produce can damage satellites, disrupt telecommunications and GPS navigation, and endanger astronauts in space. Many of the processes involved in triggering, driving, and sustaining solar eruptive events–including magnetic reconnection, particle acceleration, plasma heating, and energy transport in magnetized plasmas–also play important roles in phenomena throughout the Universe, such as in magnetospheric substorms, gamma-ray bursts, and accretion disks. The Sun is a unique laboratory to better understand these fundamental physical processes. -
Solar Science Timeline Final Wnasa ID
National Aeronautics and Space Administration Solar LAUNCH Windand A mission to travel directly through the Sun’s corona, providing up-close observations on what heats the solar atmosphere and accelerates CoronaTimeline the solar wind. Slow Solar Wind and Helmet Streamers Using observations from the joint ESA/NASA Solar and Heliospheric Observatory, Neil R. Sheeley Jr. and colleagues identify puffs of slow solar wind emanating from helmet streamers — bright areas of the corona that form above magnetically active regions on the photosphere. Exactly how these puffs are formed is still not known. The Sun’s Poles Ulysses, a joint NASA-ESA mission, becomes the first mission to fly over the Sun’s north and south poles. Among other findings, Ulysses found that in periods of minimal solar activity, the fast solar wind comes from the poles, while the slow solar wind comes from equatorial regions. Nanoflares May Heat the Corona 2018 Eugene Parker proposes that frequent, small eruptions on the Sun — known as nanoflares — may heat the corona to its extreme temperatures. The nanoflare 1995 theory contrasts with the wave theory, in which heating is caused by the dissipation of Alfvén waves. 1990 Fast Wind from Coronal Holes Images from Skylab, the U.S.’s first manned space station, identify that the fast solar wind is emitted from coronal holes — comparatively cool regions of the corona where the Sun’s magnetic field lines open out into space. 1988 The Slow and Fast Solar Wind NASA’s Mariner 2 spacecraft observes the solar wind, 1973 detecting two distinct ‘streams’ within it: a slow stream travelling at approximately 215 miles per second, and a fast stream at 430 miles per second. -
Coronal Loops in a Box: 3D Models of Their Internal Structure, Dynamics and Heating
EGU21-13091 https://doi.org/10.5194/egusphere-egu21-13091 EGU General Assembly 2021 © Author(s) 2021. This work is distributed under the Creative Commons Attribution 4.0 License. Coronal loops in a box: 3D models of their internal structure, dynamics and heating Cosima Breu, Hardi Peter, Robert Cameron, Sami Solanki, Pradeep Chitta, and Damien Przybylski Max Planck Institute for Solar System Research, Sun and Heliosphere, Germany ([email protected]) The corona of the Sun, and probably also of other stars, is built up by loops defined through the magnetic field. They vividly appear in solar observations in the extreme UV and X-rays. High- resolution observations show individual strands with diameters down to a few 100 km, and so far it remains open what defines these strands, in particular their width, and where the energy to heat them is generated. The aim of our study is to understand how the magnetic field couples the different layers of the solar atmosphere, how the energy generated by magnetoconvection is transported into the upper atmosphere and dissipated, and how this process determines the scales of observed bright strands in the loop. To this end, we conduct 3D resistive MHD simulations with the MURaM code. We include the effects of heat conduction, radiative transfer and optically thin radiative losses. We study an isolated coronal loop that is rooted with both footpoints in a shallow convection zone layer. To properly resolve the internal structure of the loop while limiting the size of the computational box, the coronal loop is modelled as a straightened magnetic flux tube. -
Multi-Spacecraft Analysis of the Solar Coronal Plasma
Multi-spacecraft analysis of the solar coronal plasma Von der Fakultät für Elektrotechnik, Informationstechnik, Physik der Technischen Universität Carolo-Wilhelmina zu Braunschweig zur Erlangung des Grades einer Doktorin der Naturwissenschaften (Dr. rer. nat.) genehmigte Dissertation von Iulia Ana Maria Chifu aus Bukarest, Rumänien eingereicht am: 11.02.2015 Disputation am: 07.05.2015 1. Referent: Prof. Dr. Sami K. Solanki 2. Referent: Prof. Dr. Karl-Heinz Glassmeier Druckjahr: 2016 Bibliografische Information der Deutschen Nationalbibliothek Die Deutsche Nationalbibliothek verzeichnet diese Publikation in der Deutschen Nationalbibliografie; detaillierte bibliografische Daten sind im Internet über http://dnb.d-nb.de abrufbar. Dissertation an der Technischen Universität Braunschweig, Fakultät für Elektrotechnik, Informationstechnik, Physik ISBN uni-edition GmbH 2016 http://www.uni-edition.de © Iulia Ana Maria Chifu This work is distributed under a Creative Commons Attribution 3.0 License Printed in Germany Vorveröffentlichung der Dissertation Teilergebnisse aus dieser Arbeit wurden mit Genehmigung der Fakultät für Elektrotech- nik, Informationstechnik, Physik, vertreten durch den Mentor der Arbeit, in folgenden Beiträgen vorab veröffentlicht: Publikationen • Mierla, M., Chifu, I., Inhester, B., Rodriguez, L., Zhukov, A., 2011, Low polarised emission from the core of coronal mass ejections, Astronomy and Astrophysics, 530, L1 • Chifu, I., Inhester, B., Mierla, M., Chifu, V., Wiegelmann, T., 2012, First 4D Recon- struction of an Eruptive Prominence -
Understanding Solar Flares and Coronal Heating at Present
The Case for Comprehensive Spectroscopic Measurements of the Sun: Understanding Solar Flares and Coronal Heating Jeffrey W. Brosius (Catholic University of America at NASA/GSFC) Peter R. Young, James A. Klimchuk (NASA/GSFC) At present the solar physics community’s efforts are largely focused on answering two of the overarching, unresolved questions in the field: (1) What heats the solar corona? (2) What causes the sudden, rapid release of en- ergy that produces flares? Comprehensive spectroscopic measurements are essential to answer these questions. The solar atmosphere along any given line of sight emits optically thin radiation from plasma over widely ranging temperatures. This is true no matter what solar feature is observed, from flares and quiescent active regions to quiet Sun areas and coronal holes. The range of temperature is larger during flares than it is in quiet areas or coronal holes, but in all cases it exceeds an order of magnitude. For example, the temperature of the upper chromosphere is around 20,000 K (log T = 4.3); during flares, plasma is > heated to tens of million Kelvin (log T ∼ 7.3), so the range of temperatures observed along a line of sight can exceed three orders of magnitude. In quiescent active regions the “typical” coronal temperature is around 3 MK, while in coronal holes and quiet Sun areas it is 1 - 2 MK; in these cases the range of temperatures is close to two orders of magnitude. To understand what initiates the release of flare energy, how that energy is transported throughout the flaring region, and how the atmosphere evolves in response, spectroscopic measurements are required over the entire range of temperature that occurs during flares. -
GSFC Heliophysics Science Division 2009 Science Highlights
NASA/TM–2010–215854 GSFC Heliophysics Science Division 2009 Science Highlights Holly R. Gilbert, Keith T. Strong, Julia L.R. Saba, and Yvonne M. Strong, Editors December 2009 Front Cover Caption: Heliophysics image highlights from 2009. For details of these images, see the key on Page v. The NASA STI Program Offi ce … in Profi le Since its founding, NASA has been ded i cated to the • CONFERENCE PUBLICATION. Collected ad vancement of aeronautics and space science. The pa pers from scientifi c and technical conferences, NASA Sci en tifi c and Technical Information (STI) symposia, sem i nars, or other meetings spon sored Pro gram Offi ce plays a key part in helping NASA or co spon sored by NASA. maintain this impor tant role. • SPECIAL PUBLICATION. Scientifi c, techni cal, The NASA STI Program Offi ce is operated by or historical information from NASA pro grams, Langley Research Center, the lead center for projects, and mission, often concerned with sub- NASAʼs scientifi c and technical infor ma tion. The jects having substan tial public interest. NASA STI Program Offi ce pro vides ac cess to the NASA STI Database, the largest collec tion of • TECHNICAL TRANSLATION. En glish-language aero nau ti cal and space science STI in the world. trans la tions of foreign scien tifi c and techni cal ma- The Pro gram Offi ce is also NASAʼs in sti tu tion al terial pertinent to NASAʼs mis sion. mecha nism for dis sem i nat ing the results of its research and devel op ment activ i ties. -
Solar Orbiter and Sentinels
HELEX: Heliophysical Explorers: Solar Orbiter and Sentinels Report of the Joint Science and Technology Definition Team (JSTDT) PRE-PUBLICATION VERSION 1 Contents HELEX Joint Science and Technology Definition Team .................................................................. 3 Executive Summary ................................................................................................................................. 4 1.0 Introduction ........................................................................................................................................ 6 1.1 Heliophysical Explorers (HELEX): Solar Orbiter and the Inner Heliospheric Sentinels ........ 7 2.0 Science Objectives .............................................................................................................................. 8 2.1 What are the origins of the solar wind streams and the heliospheric magnetic field? ............. 9 2.2 What are the sources, acceleration mechanisms, and transport processes of solar energetic particles? ........................................................................................................................................ 13 2.3 How do coronal mass ejections evolve in the inner heliosphere? ............................................. 16 2.4 High-latitude-phase science ......................................................................................................... 19 3.0 Measurement Requirements and Science Implementation ........................................................ 20 -
Why Is the Sun's Corona So Hot? Why Are Prominences So Cool?
Why is the Sun’s corona so hot? Why are prominences so cool? Jack B. Zirker and Oddbjørn Engvold Citation: Physics Today 70, 8, 36 (2017); doi: 10.1063/PT.3.3659 View online: http://dx.doi.org/10.1063/PT.3.3659 View Table of Contents: http://physicstoday.scitation.org/toc/pto/70/8 Published by the American Institute of Physics Why is the Sun’s corona so hot? Why are prominences so cool? Jack B. Zirker and Oddbjørn Engvold Over the past several decades, solar physicists have made steady progress in answering the COURTESY OF SHADIA HABBAL two long-standing questions, but puzzles remain. Jack Zirker is an astronomer emeritus at the National Solar Observatory’s facilities on Sacramento Peak in Sunspot, New Mexico. Oddbjørn Engvold is an emeritus professor at the University of Oslo’s Institute of Theoretical Astrophysics in Oslo, Norway. n the 21st of this month, millions of enthusiasts found between the x-ray brightness of active regions—hot plasma-filled in the US will be treated to a total eclipse of the aggregations of looped magnetic field Sun. During two minutes of darkness, they lines—and the strength of their surface will see—weather permitting—the extremely magnetic fields. That important clue O suggested that magnetic fields must faint outer atmosphere of the Sun, the corona. play an important role in heating the They may also see red feathery sheets of gas called prominences corona. In a parallel development, Eugene immersed in the corona. Parker predicted in 1958 that a hot co- rona must expand into space as a solar Since the 1940s astronomers have known that the corona is wind. -
The Highenergy Sun at High Sensitivity: a Nustar Solar Guest
The High-Energy Sun at High Sensitivity: a NuSTAR Solar Guest Investigation Program A concept paper submitted to the Space Studies Board Heliophysics Decadal Survey by David M. Smith, Säm Krucker, Gordon Hurford, Hugh Hudson, Stephen White, Fiona Harrison (NuSTAR PI), and Daniel Stern (NuSTAR Project Scientist) Figure 1: Artist©s conception of the NuSTAR spacecraft Introduction and Overview Understanding the origin, propagation and fate of non-thermal electrons is an important topic in solar and space physics: it is these particles that present a danger for interplanetary probes and astronauts, and also these particles that carry diagnostic information that can teach us about acceleration processes elsewhere in the heliosphere and throughout the universe. Such non-thermal electrons can be detected via their X-ray or gamma-ray emission, their radio emission, or directly in situ in interplanetary space. To date, the state of the art in solar hard x-ray imaging has been the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI), a NASA Small Explorer satellite launched in 2002, which uses an indirect imaging method (rotating modulation collimators) for hard x-ray imaging. This technique can provide high angular resolution, but it is limited in dynamic range and in sensitivity to small events, due to high background. High-energy imaging of the active Sun is technically easiest in the soft x-ray band (see, for example, the detailed and dynamic images returned by the soft x- ray imager on Hinode, as well as the corresponding telescopes on Yohkoh and GOES), but these x-rays are generally emitted by lower-energy thermal plasmas. -
10 Years of SOHO and Beyond Sunday, 7 May 2006, AM Monday
SOHO 17: 10 Years of SOHO and Beyond 7-12 May 2006, Giardini Naxos, Sicily Sunday, 7 May 2006, AM 16:00-18:00 Early Bird Check-In at Naxos Beach Resort 19:00 Welcome Reception at Naxos Beach Resort Monday, 8 May 2006, AM Chairs: Thompson, Mike; Di Mauro, Maria Pia 08:00 Registration at Palanaxos 09:00 Welcome Address Flamini, Fabrizio Agenzia Spaziale Italiana Session 1: Solar Interior: From Exploration to Experimentation Time: 09:05 - 12:30 09:05 Helioseismological Determination of the State of the Solar p.1 Interior Gough, Douglas University of Cambridge 09:35 Interpreting Solar Frequencies: Methods and Techniques p.2 Basu, Sarbani Yale University 10:05 Recent Progresses on g-mode Search p.3 Appourchaux, Thierry et al. Institut d'Astrophysique Spatiale 10:20 Looking for Asymptotic G Modes using GOLF Aboard SoHO p.4 Garcia, Rafael A. et al. Service d'Astrophysique CEA/Saclay 10:35 – 11:15 Coffee Break and Posters at the Palanaxos 11:15 Helioseismic Determination of Subsurface Fluid Dynamics p.5 Corbard, Thierry Observatoire de la Cτte d'Azur, FRANCE 11:45 SOHO and Time-Distance Helioseismology p.6 Duvall, Thomas1 et al. NASA/Goddard Space Flight Center 12:00 Subsurface Flows and the Evolution of Solar Filaments p.7 Hindman, Bradley1 et al. University of Colorado 12:15 Resonant Oscillation Modes and Background in Realistic p.8 Hydrodynamical Simulations of Solar Surface Convection Straus, T.1 et al. INAF - Osservatorio Astronomico di Capodimonte 12:30 – 14:30 Luncheon at the Naxos Beach Hotel SOHO 17 Provisional Programme (subject to change) ii Monday, 8 May 2006, PM Chairs: Vial, Jean-Claude; Gregory, Sara Session 2: Magnetic Variability: From the Tachocline to the Heliosphere Time: 14:30 - 17:30 14:30 Probing Solar Activity and Convection with Local p.9 Helioseismology Gizon, Laurent Max-Planck-Institut fuer Sonnensystemforschung, 15:00 The Solar Dynamo: What we know, what we think we know p.10 and what progress can we make. -
Waves and Magnetism in the Solar Atmosphere (WAMIS)
METHODS published: 16 February 2016 doi: 10.3389/fspas.2016.00001 Waves and Magnetism in the Solar Atmosphere (WAMIS) Yuan-Kuen Ko 1*, John D. Moses 2, John M. Laming 1, Leonard Strachan 1, Samuel Tun Beltran 1, Steven Tomczyk 3, Sarah E. Gibson 3, Frédéric Auchère 4, Roberto Casini 3, Silvano Fineschi 5, Michael Knoelker 3, Clarence Korendyke 1, Scott W. McIntosh 3, Marco Romoli 6, Jan Rybak 7, Dennis G. Socker 1, Angelos Vourlidas 8 and Qian Wu 3 1 Space Science Division, Naval Research Laboratory, Washington, DC, USA, 2 Heliophysics Division, Science Mission Directorate, NASA, Washington, DC, USA, 3 High Altitude Observatory, Boulder, CO, USA, 4 Institut d’Astrophysique Spatiale, CNRS Université Paris-Sud, Orsay, France, 5 INAF - National Institute for Astrophysics, Astrophysical Observatory of Torino, Pino Torinese, Italy, 6 Department of Physics and Astronomy, University of Florence, Florence, Italy, 7 Astronomical Institute, Slovak Academy of Sciences, Tatranska Lomnica, Slovakia, 8 Applied Physics Laboratory, Johns Hopkins University, Laurel, MD, USA Edited by: Mario J. P. F. G. Monteiro, Comprehensive measurements of magnetic fields in the solar corona have a long Institute of Astrophysics and Space Sciences, Portugal history as an important scientific goal. Besides being crucial to understanding coronal Reviewed by: structures and the Sun’s generation of space weather, direct measurements of their Gordon James Duncan Petrie, strength and direction are also crucial steps in understanding observed wave motions. National Solar Observatory, USA Robertus Erdelyi, In this regard, the remote sensing instrumentation used to make coronal magnetic field University of Sheffield, UK measurements is well suited to measuring the Doppler signature of waves in the solar João José Graça Lima, structures. -
Imaging Coronal Magnetic-Field Reconnection in a Solar Flare
LETTERS PUBLISHED ONLINE: 14 JULY 2013 | DOI: 10.1038/NPHYS2675 Imaging coronal magnetic-field reconnection in a solar flare Yang Su1*, Astrid M. Veronig1, Gordon D. Holman2, Brian R. Dennis2, Tongjiang Wang2,3, Manuela Temmer1 and Weiqun Gan4 Magnetic-field reconnection is believed to play a fundamental plasmoid ejection20. However, most evidence has been indirect and role in magnetized plasma systems throughout the Universe1, fragmented. Detailed observations of the complete picture are still including planetary magnetospheres, magnetars and accretion missing owing to the highly dynamic flare/CME process and limited disks around black holes. This letter presents extreme ultravi- observational capabilities. olet and X-ray observations of a solar flare showing magnetic The launch of the Solar Dynamic Observatory21 (SDO) in 2010 reconnection with a level of clarity not previously achieved. significantly improved this situation. In particular, the Atmospheric The multi-wavelength extreme ultraviolet observations from Imaging Assembly22 (AIA) has enabled continuous imaging of SDO/AIA show inflowing cool loops and newly formed, out- the full Sun in ten extreme ultraviolet (EUV), ultraviolet and flowing hot loops, as predicted. RHESSI X-ray spectra and visible channels, with a spatial resolution of ∼0.6 arcsec and a images simultaneously show the appearance of plasma heated cadence of 12 s. Simultaneously, the Ramaty High Energy Solar to >10 MK at the expected locations. These two data sets Spectroscopic Imager23 (RHESSI) is continuing to provide X-ray provide solid visual evidence of magnetic reconnection pro- imaging and spectroscopic diagnostics of the heated plasma and ducing a solar flare, validating the basic physical mechanism accelerated electrons.