GSFC Heliophysics Science Division 2009 Science Highlights
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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. -
Our Dynamic Sun: 2017 Hannes Alfvén Medal Lecture at the EGU
Ann. Geophys., 35, 805–816, 2017 https://doi.org/10.5194/angeo-35-805-2017 © Author(s) 2017. This work is distributed under the Creative Commons Attribution 3.0 License. Our dynamic sun: 2017 Hannes Alfvén Medal lecture at the EGU Eric Priest1,* 1Mathematics Institute, St Andrews University, St Andrews KY16 9SS, UK *Invited contribution by Eric Priest, recipient of the EGU Hannes Alfvén Medal for Scientists 2017 Correspondence to: Eric Priest ([email protected]) Received: 15 May 2017 – Accepted: 12 June 2017 – Published: 14 July 2017 Abstract. This lecture summarises how our understanding 1 Introduction of many aspects of the Sun has been revolutionised over the past few years by new observations and models. Much of the Thank you most warmly for the award of the Alfvén Medal, dynamic behaviour of the Sun is driven by the magnetic field which gives me great pleasure. In addition to a feeling of since, in the outer atmosphere, it represents the largest source surprise, I am also deeply humbled, because Alfvén was one of energy by far. of the greats in the field and one of my heroes as a young The interior of the Sun possesses a strong shear layer at the researcher (Fig. 1). We need dedicated scientists who fol- base of the convection zone, where sunspot magnetic fields low a specialised topic with tenacity and who complement are generated. A small-scale dynamo may also be operating one another in our amazingly diverse field; but we also need near the surface of the Sun, generating magnetic fields that time and space for creativity in this busy world, especially thread the lowest layer of the solar atmosphere, the turbulent for those princes of creativity, mavericks like Alfvén who can photosphere. -
Large-Scale Periodic Solar Velocities
LARGE-SCALE PERIODIC SOLAR VELOCITIES: AN OBSERVATIONAL STUDY (NASA-CR-153256) LARGE-SCALE PERIODIC SOLAR N77-26056 ElOCITIeS: AN OBSERVATIONAL STUDY Stanford Univ.) 211 p HC,A10/F A01 CSCL 03B Unclas G3/92 35416 by Phil Howard Dittmer Office of Naval Research Contract N00014-76-C-0207 National Aeronautics and Space Administration Grant NGR 05-020-559 National Science Foundation Grant ATM74-19007 Grant DES75-15664 and The Max C.Fleischmann Foundation SUIPR Report No. 686 T'A kj, JUN 1977 > March 1977 RECEIVED NASA STI FACILITY This document has been approved for public INPUT B N release and sale; its distribution isunlimited. 4 ,. INSTITUTE FOR PLASMA RESEARCH STANFORD UNIVERSITY, STANFORD, CALIFORNIA UNCLASSIFIED SECURITY CLASSIFICATION OF THIS PAGE (When Data Entered) DREAD INSTRUCTIONS REPORT DOCUMENTATION PAGE BEFORE COMPLETING FORM I- REPORT NUMBER 2 GOVT ACCESSION NO. 3. RECIPIENT'S CATALOG NUMBER SUIPR Report No. 686 4. TITLE (and Subtitle) 5 TYPE OF REPORT & PERIOD COVERED Large-Scale Periodic Solar Velocities: Scientific, Technical An Observational Study 6. PERFORMING ORG. REPORT NUMBER 7. AUTHOR(s) 8 CONTRACT OR GRANT NUMBER(s) Phil Howard Dittmer N00014-76-C-0207 S PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMENT, PROJECT, TASK Institute for Plasma Research AREA & WORK UNIT NUMBERS Stanford University Stanford, California 94305 12. REPORT DATE . 13. NO. OF PAGES 11. CONTROLLING OFFICE NAME AND ADDRESS March 1977 211 Office of Naval Research Electronics Program Office 15. SECURITY CLASS. (of-this report) Arlington, Virginia 22217 Unclassified 14. MONITORING AGENCY NAME & ADDRESS (if diff. from Controlling Office) 15a. DECLASSIFICATION/DOWNGRADING SCHEDULE 16. DISTRIBUTION STATEMENT (of this report) This document has been approved for public release and sale; its distribution is unlimited. -
THE PROPER TREATMENT of CORONAL MASS EJECTION BRIGHTNESS: a NEW METHODOLOGY and IMPLICATIONS for OBSERVATIONS Angelos Vourlidas and Russell A
The Astrophysical Journal, 642:1216–1221, 2006 May 10 A # 2006. The American Astronomical Society. All rights reserved. Printed in U.S.A. THE PROPER TREATMENT OF CORONAL MASS EJECTION BRIGHTNESS: A NEW METHODOLOGY AND IMPLICATIONS FOR OBSERVATIONS Angelos Vourlidas and Russell A. Howard Code 7663, Naval Research Laboratory, Washington, DC 20375; [email protected] Received 2005 November 10; accepted 2005 December 30 ABSTRACT With the complement of coronagraphs and imagers in the SECCHI suite, we will follow a coronal mass ejection (CME) continuously from the Sun to Earth for the first time. The comparison, however, of the CME emission among the various instruments is not as easy as one might think. This is because the telescopes record the Thomson-scattered emission from the CME plasma, which has a rather sensitive dependence on the geometry between the observer and the scattering material. Here we describe the proper treatment of the Thomson-scattered emission, compare the CME brightness over a large range of elongation angles, and discuss the implications for existing and future white-light coronagraph observations. Subject headinggs: scattering — Sun: corona — Sun: coronal mass ejections (CMEs) Online material: color figures 1. INTRODUCTION some important implications resulting from dropping this as- It is long been established that white-light emission of the co- sumption. We conclude in x 4. rona originates by Thomson scattering of the photospheric light by coronal electrons (e.g., Minnaert 1930). Coronal mass ejec- 2. THOMSON SCATTERING GEOMETRY tions (CMEs) comprise a spectacular example of this process and The theory behind Thomson scattering is well understood are regularly recorded by ground-based and space-based corona- (Jackson 1997). -
On the Autonomous Detection of Coronal Mass Ejections in Heliospheric Imager Data S
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 117, A05103, doi:10.1029/2011JA017439, 2012 On the autonomous detection of coronal mass ejections in heliospheric imager data S. J. Tappin,1 T. A. Howard,2 M. M. Hampson,1,3 R. N. Thompson,2,4 and C. E. Burns2,5 Received 7 December 2011; revised 3 April 2012; accepted 9 April 2012; published 24 May 2012. [1] We report on the development of an Automatic Coronal Mass Ejection (CME) Detection tool (AICMED) for the Solar Mass Ejection Imager (SMEI). CMEs observed with heliospheric imagers are much more difficult to detect than those observed by coronagraphs as they have a lower contrast compared with the background light, have a larger range of intensity variation and are easily confused with other transient activity. CMEs appear in SMEI images as very faint often-fragmented arcs amongst a much brighter and often variable background. AICMED operates along the same lines as Computer Aided CME Tracking (CACTus), using the Hough Transform on elongation-time J-maps to extract straight lines from the data set. We compare AICMED results with manually measured CMEs on almost three years of data from early in SMEI operations. AICMED identified 83 verifiable events. Of these 46 could be matched with manually identified events, the majority of the non-detections can be explained. The remaining 37 AICMED events were newly discovered CMEs. The proportion of false identification was high, at 71% of the autonomously detected events. We find that AICMED is very effective as a region of interest highlighter, and is a promising first step in autonomous heliospheric imager CME detection, but the SMEI data are too noisy for the tool to be completely automated. -
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. -
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 New Heliophysics Division Template
NASA Heliophysics Division Update Heliophysics Advisory Committee October 1, 2019 Dr. Nicola J. Fox Director, Heliophysics Division Science Mission Directorate 1 The Dawn of a New Era for Heliophysics Heliophysics Division (HPD), in collaboration with its partners, is poised like never before to -- Explore uncharted territory from pockets of intense radiation near Earth, right to the Sun itself, and past the planets into interstellar space. Strategically combine research from a fleet of carefully-selected missions at key locations to better understand our entire space environment. Understand the interaction between Earth weather and space weather – protecting people and spacecraft. Coordinate with other agencies to fulfill its role for the Nation enabling advances in space weather knowledge and technologies Engage the public with research breakthroughs and citizen science Develop the next generation of heliophysicists 2 Decadal Survey 3 Alignment with Decadal Survey Recommendations NASA FY20 Presidential Budget Request R0.0 Complete the current program Extended operations of current operating missions as recommended by the 2017 Senior Review, planning for the next Senior Review Mar/Apr 2020; 3 recently launched and now in primary operations (GOLD, Parker, SET); and 2 missions currently in development (ICON, Solar Orbiter) R1.0 Implement DRIVE (Diversify, Realize, Implemented DRIVE initiative wedge in FY15; DRIVE initiative is now Integrate, Venture, Educate) part of the Heliophysics R&A baseline R2.0 Accelerate and expand Heliophysics Decadal recommendation of every 2-3 years; Explorer mission AO Explorer program released in 2016 and again in 2019. Notional mission cadence will continue to follow Decadal recommendation going forward. Increased frequency of Missions of Opportunity (MO), including rideshares on IMAP and Tech Demo MO.