DOCSLIB.ORG

SECCHI/Heliospheric Imager Science Studies Sarah Matthews Mullard

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
SECCHI/Heliospheric Imager Science Studies Sarah Matthews Mullard SECCHI/Heliospheric Imager Science Studies Sarah Matthews Mullard Space Science Laboratory University College London Holmbury St. Mary, Dorking Surrey RH5 6NT [email protected] Version 2, 12 December 2003 1. Introduction This document is intended to provide a focus for the scientific operation of the Heliospheric Imager camera systems that form part of the SECCHI instrument payload on STEREO. Its purpose is to provide a brief introduction to the instruments and their capabilities, within the context of the SECCHI instrumentation as a whole, and to outline a series of proposed science studies whose primary focus requires the HI1 and/or HI2, although this does not preclude the inclusion of studies whose main focus is another of the SECCHI instruments. In addition to defining the science goals for the HI these science studies also provide operational constraints that as far as possible will be fed into the on-board software requirements. In order to obtain a detailed view of the instruments, the science goals and operations, it is recommended that this document should be used together with the Heliospheric Imager Operations Document written by Richard Harrison and the Image Simulation document written by Chris Davis & Richard Harrison. 2. SECCHI and the Heliospheric Imager SECCHI is a set of remote sensing instruments designed to follow Coronal Mass Ejections (CMEs) from their origins on the Sun, out through the corona and the interplanetary medium and to possible impact with the Earth. The instrument package comprises 3 telescopes: ÿ EUV Imaging Telescope (EUVI) - a full Sun instrument which images the chromosphere and corona in 4 emission lines: He II 304 A, Fe IX/X 171 A, Fe XII 195 A and Fe XV 284 A. ÿ COR 1 and COR 2 - two white-light coronagraphs to observe the inner (1.1-3 solar radii) and outer (2-15 solar radii) corona at high temporal and spatial resolution, and provide polarization information. ÿ Heliospheric Imager (HI1 and HI2) - these are externally occulted coronagraphs that image the inner heliosphere between the Sun and the Earth between 12-215 solar radii. STEREO is the first mission dedicated to understanding the physics of CMEs and their effects on the Earth's environment. The mission's overall science objectives are as follows: ÿ Understand the causes and mechanisms of CME inititation ÿ Characterize the propagation of CMEs through the Heliosphere ÿ Discover the mechanisms and sites of energetic particle acceleration in the low corona and the interplanetary medium ÿ Improve determination of the structure of the ambient solar wind Within these objectives SECCHI has its own primary science goals to: ÿ Determine the 3D structure of coronal loops, coronal streamers and large-scale coronal structures ÿ Determine the 3D properties of CMEs ÿ Determine the timing of physical properties involved in CME initiation ÿ Determine the critical forces controlling propagation of CMEs in the corona and interplanetary medium. The HI instruments, with their unique FOV, will provide the first direct imaging observations of CMEs in the inner heliosphere. As such they will directly address the issue of the forces that control CME evolution and propagation in the corona inner heliopshere, as well as providing insights into the mechanisms and sites of particle acceleration in this region and space weather alerts. 3. Heliospheric Imager characteristics A detailed description of the design of the Heliospheric Imager can be found in the operations document and in Socker et al., 2000. The basic concept uses occultation and a baffle system to achieve the light rejection levels necessary to provide wide-angle views of the heliosphere. The two cameras are centred on the Earth-Sun line with two circular fields of view of 20o (HI-1) and 70o (HI-2), offset from the Sun at 13.65o and 53.35o, respectively. This allows us to view the whole Sun-Earth line from 12 solar radii to near Earth orbit. The detectors are CCDs of 2048x2048 13.5 micron pixels which are usually binned on board to give images of size 1024x1024 pixels, with a resolution of 70 arcsec (HI-1) and 4 arc mins (HI-2). Nominal exposure times are in the range 12-20 s for HI-1 and 60-90s for HI-2. Note that the nominal cadence for each camera is 60 min (HI-1) and 120 min (HI-2). The driver behind these numbers is the need to accumulate sufficient signal to noise and to remove cosmic rays from each exposure prior to summing to produce the image. These characteristics are summarised in Table 1 of the operations document, which we reproduce below for convenience. HI-1 HI-2 Instrument Type Externally occulted Externally occulted coronagraph coronagraph Centre of Field-of-view Along Sun-Earth line Along Sun-Earth line Direction q = 13.65 degrees q = 53.35 degrees Angular field-of-view 20 degrees 70 degrees Coronal coverage 12-84 Rsun 66-318 Rsun Overlap with COR-2 12-15 Rsun N/A Overlap with HI-1 N/A 66-84 Rsun Baseline image (2x2 1024x1024 1024x1024 binning) Image pixel scale 70 arcsec 4 arc min (binned) (binned) Spectral bandpass 630 – 730 nm 400 – 1000 nm Exposure time 12 –20 s 60 – 90 s Nominal images per 70 60 sequence Required cadence 60 min 120 min -15 -16 Brightness sensitivity 3 x 10 Bsun 3 x 10 Bsun -13 -14 Straylight rejection 3 x 10 Bsun 10 Bsun Brightness accuracy 10% 10% Table 1:Characteristics of the Heliospheric Imager 4. Science scenarios The default mode of operation of STEREO is a synoptic one , with the synoptic operation of the HI based on the values given in Table 1. However, SECCHI, and the HI in particular, can be used to answer a wide range of scientific questions, some of which will fall outside of the scope of the synoptic operational mode. In order to assess the range of operational requirements that may be needed, from an HI perspective in particular, the UK SECCHI/STEREO science team has considered a range of different scientific problems and the instrumental and operational caveats associated with them. To ensure a degree of uniformity a schema was provided for people that outlined the basic instrumental choices and the synoptic fields of view, exposure times, cadences etc. In addition people were asked to consider whether co-ordination with other instruments on STEREO was required, or with other spacecraft and ground-based facilities, since these clearly raise more complicated planning issues. The resulting 15 science questions are listed below in Table 2 along with their authors and institutes. The scientific justification and detailed observational requirements can be found in section 5 of this document. Study Author 1. Impact of CME on the Earth Richard Harrison (RAL) 2. CMEs in interplanetary space Peter Cargill (IC) 3. Understanding how observations Peter Cargill (IC) at L1 & SECCHI are related 4. 3-D structure of interplanetary CMEs Lucie Green (Cardiff) 5. CME onset Sarah Matthews (MSSL) 6. The relationship between CMEs and Sarah Matthews (MSSL) magnetic clouds 7. Particle acceleration at CME shocks Sarah Matthews (MSSL) 8. Synoptic CME programme Richard Harrison (RAL) 9. Solar wind microstructure Andy Breen (Aberystwyth) 10. Development of co-rotating interaction Andy Breen (Aberystwyth) regions 11. Differential drift velocities in the fast & Andy Breen (Aberystwyth) slow solar winds 12. Boundary regions between fast & slow Andy Breen (Aberystwyth) streams in the solar wind 13. Remote solar wind speed & direction Geraint Jones (IC) measurements from 3-D observations of cometary ion tails 14. Interplanetary acceleration of ICMEs Mathew Owens (IC) 15. Beacon mode Sarah Matthews (MSSL), Richard Harrison & Chris Davis (RAL) Table 2: list of science scenarios 5. Science scenarios Observation Title: Impact of CME on the Earth Name: Richard Harrison Institute: RAL E-mail: [email protected] Version Date: 1 May 2002 Brief Scientific Objective and Observation Overview: One of the principal aims of STEREO is to enable a better understanding of the arrival and impact of CMEs on the Earth. Thus, a major goal is the direct observation of a CME event arriving at Earth. For this, the prime instrument here is HI2, which has the Earth and CME within its field of view. However, the support of HI1, COR1 and COR2 is required to provide the most complete understanding of the CME structure and evolution as it propagates from the Sun. Sequence Details EUVI: [Bands - He II 304, Fe IX 171, Fe XII 195, Fe XV 284 Å; Resolution - 1.6 arcsec/pixel; FOV - 0.9 deg Sun-centred; Nominal cadence 30 s] ÿ Required (yes/no) - No ÿ Which bands? - n/a ÿ Image cadence? - n/a ÿ FOV (full Sun, partial Sun (define area and pointing)) - n/a ÿ Other details - n/a COR1: [Bandpass - 650-660 nm (brightness and pB); Resolution - 7.5 arcsec/pixel; FOV - 1.3-4.0 R (full revolution; Sun centred); Nominal cadence 20 s (3 images/min in different polarisation angles)] ÿ Required (yes/no) - Yes ÿ Image cadence? nominal ÿ FOV (full or partial field (define area and pointing)) - full ÿ Other details COR2: [Bandpass - 650-750 nm (brightness and pB); Resolution - 15 arcsec/pixel; FOV - 2-15 R (full revolution; Sun centred); Nominal cadence 100 s] ÿ Required (yes/no) - Yes ÿ Image cadence? - nominal ÿ FOV (full or partial field (define area and pointing)) - full ÿ Other details HI1: [Bandpass - 650-750 nm (brightness); Resolution - 35 arcsec/pixel; FOV - 20o circle centred at 13.28o to Sun centre (3.28-23.28o along ecliptic); Nominal cadence 1 hr] ÿ Required (yes/no) - Yes ÿ Image cadence? - nominal ÿ FOV (full or partial field (define area and pointing)) - full ÿ Other details HI2: [Bandpass - 400-1000 nm (brightness); Resolution - 240 arcsec/pixel; FOV - 70o circle centred at 53.36o to Sun centre (18.36-88.36o along ecliptic); Nominal cadence 2 hr] ÿ Required (yes/no) - Yes ÿ Image cadence? - 2 hr ÿ FOV (full or partial field (define area and pointing)) - see details Other details Cadence sized for fast (1000 km/s) CME travelling from 73 to 212 solar radii, i.e.
Load more

Recommended publications
  • 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).
    [Show full text]
  • 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.
    [Show full text]
  • 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.
    [Show full text]
  • 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.
    [Show full text]
  • Design of the Heliospheric Imager for the STEREO Mission
    Design of the Heliospheric Imager for the STEREO mission Jean-Marc Defisea∗, Jean-Philippe Halaina, Emmanuel Mazya, Russel A. Howardb, Clarence M. Korendykeb, Pierre Rochusa, George M. Simnettc, Dennis G. Sockerb*, David F. Webbd aCentre Spatial de Liège, 4031 Angleur, Belgium bNaval Research Laboratory, Washington, DC 20375 cUniversity of Birmingham, Birmingham B15217, United Kingdom dBoston College, Chestnut Hill, MA 02467 ABSTRACT The Heliospheric Imager (HI) is part of the SECCHI suite of instruments on-board the two STEREO spacecrafts. The two HI instruments will provide stereographic image pairs of solar coronal plasma and address the observational problem of very faint coronal mass ejections (CME) over a wide field of view (~90°) ranging from 12 to 250 R-0. The key element of the instrument design is to reject the solar disk light, with stray-light attenuation of the order of 10-12 to 10-15 in the camera systems. This attenuation is accomplished by a specific design of stray-light baffling system, and two separate observing cameras with complimentary FOV’s cover the wide field of view. A multi-vane diffractive system has been theoretically optimized to achieve the lower requirement (10-13 for HI-1) and is combined with a secondary baffling system to reach the 10-15 rejection performance in the second camera system (HI-2). This paper presents the design concept of the HI, and the preparation of verification tests that will demonstrate the instrument performances. The baffle design has been optimized according to accommodation constrains on the spacecraft, and the optics were studied to provide adequate light gathering power.
    [Show full text]
  • SOLARNET IV MEETING the Physics of the Sun from the Interior to the Outer Atmosphere Lanzarote, Spain, 16-20 January 2017
    SOLARNET IV MEETING The Physics of the Sun from the Interior to the Outer Atmosphere Lanzarote, Spain, 16-20 January 2017 PROGRAMME MONDAY, JAN 16TH 8:00 – 9:00 Registration 9:00 – 9:10 Welcome E. Khomenko & MJ Martínes-González 9:10 – 9:30 The SOLARNET project M. Collados SESSION 1: SOLAR INTERNAL STRUCTURE FROM HELIOSEISMOLOGY 9:30 – 10:00 IR: Helioseismic probes of the solar interior Anne-Marie Broomhall 10:00 – 10:20 ST: Data assimilation as a tool to better understand the solar Laurent Jouvé magnetism 10:20 – 10:35 Halo formation in realistic 3D MHD simulations Irina Thaler 10:35 – 10:50 The Subsurface Structure of Active Regions from Measured Dean-Yi Chou Scattering Matrix Elements 10:50 – 11:05 Computation of 3d sensitivity kernels for understanding Krishnendu Mandal meridional circulation 11:05 – 11:45 Coffee break and POSTER session 11:45 – 12:05 ST: Forward modeling for local solar seismology Tobías Felipe 12:05 – 12:20 Formation of sunspots: theory and observations Illa R. Losada 12:20 – 12:35 A new physical mechanism to explain meridional Dário Passos circulation's cyclic variations 12:35 – 12:50 Deep Meridional Flow Inversions with Spherical Born Vincent Böning Kernels and Time-Distance Helioseismology 12:50 – 14:30 LUNCH (Arrecife Gran Hotel) SESSION 2: SOLAR CYCLE: CONVECTION, ROTATION, DYNAMO, FLUX EMERGENCE 14:30 – 15:00 IR: Differential rotation and convective dynamo in the solar Yuhong Fan convective envelope 15:00 – 15:20 ST: Dynamo modes as a mechanism for long-term solar Maarit Käpylä activity variations 15:20 –
    [Show full text]
  • Space Science Acronyms
    Space Science Acronyms AA Auroral radio Absorption AACGM Altitude Adjusted Corrected GeoMagnetic ABI Auroral Boundary Index ACCENT Atmospheric Chemistry of Combustion Emissions Near the Tropopause ACE Advanced Composition Explorer ACF Auto Correlation Functions ACR Anomalous Cosmic Rays ADCS Attitude Determination and Control Subsystem ADEOS ADvanced Earth Observation Satellite (Japan) ADEP ARTIST Data Editing and Printing ADMS Atmospheric Density Mass Spectrometer AE Atmosphere Explorer AE Auroral Electrojet index AEPI Atmospheric Emissions Photometric Imager AES Auger Electron Spectroscopy AEU Antenna Element Unit AFB Air Force Base AFGL Air Force Geophysical Laboratory AFIT Air Force Institute of Technology AFOSR Air Force Office of Scientific Research AFRL Air Force Research Lab AFSCN Air Force Satellite Control Network AFSPC Air Force SPace Command AFWA Air Force Weather Agency AGILE Astrorivelatore Gamma a Immagini Leggero AGU American Geophysical Union AGW Atmospheric Gravity Waves AI Asymmetry Index AIDA Arecibo Initiative in Dynamics of the Atmosphere AIM Aeronomy of Ices in the Mesosphere AKR Auroral Kilometric Radiation AL Auroral Electrojet Lower Limit Index ALF Absorption Limiting Frequency ALIS Airglow Limb Imaging System ALOMAR Arctic Lidar Observatory for Middle Atmospheric Research ALOS Advanced Land Observing Satellite ALSP Apollo Lunar Surface Probe ALTAIR ARPA Long-Range Tracking and Identification Radar AMBER African Meridian B-field Educational Research Array AMCSR Advanced Modular Coherent Scatter Radar AMI Aeronomic
    [Show full text]
  • Using Coronagraphs and Heliospheric Imagers to Answer the Outstanding Questions of Solar Wind Physics
    2/2/2021 AGU - iPosterSessions.com Using Coronagraphs and Heliospheric Imagers to Answer the Outstanding Questions of Solar Wind Physics Nicholeen M. Viall (1) and Joseph Borovsky (2) (1) NASA Goddard Space Flight Center, Greenbelt, MD, United States, (2) Space Science Institute, Los Alamos, NM, United States PRESENTED AT: https://agu2020fallmeeting-agu.ipostersessions.com/Default.aspx?s=1F-DA-4D-0F-03-CB-7D-40-2F-55-3C-62-D5-14-0B-15&pdfprint=true&guestview=true 1/12 2/2/2021 AGU - iPosterSessions.com HINDERANCES TO PROGRESS _______________________________________ There are major outstanding questions regarding solar wind formation and its evolution as it advects through the heliosphere. Synthesizing inputs from the solar wind research community, we describe nine outstanding questions of solar wind physics from a recent AGU Grand Challenges review paper (Viall & Borovsky, 2020), as well as progress expected with recent and upcoming coronagraphs and heliospheric imagers. Nine Outstanding Questions of Solar Wind Physics agupubs.onlinelibrary.wiley.com ______________________________________ Challenge 1: There is insufficient data coverage and computational power to measure and model cross-scale feedback. Observations and models need to encompass scale sizes small enough to resolve kinetic physics up through the global scales of the system. In the solar wind, these are in situ measurement timescales of milliseconds (e.g. to capture the spatial scales of electron physics) through global time scales of at least a solar rotation, a span of eight orders of magnitude. As a result, observations and models must focus on restricted regions of parameter space. Further, modeling must reduce the complexity of the phenomena it mimics: e.g.
    [Show full text]
  • Living with a Star
    space Living with a star: the many faces of the Sun Sarah Matthews UCL Mullard Space Science Lab Mullard Space Science Laboratory Why? Solar variability drives variability in the near-Earth environment ➢ Magnetic field evolution drives that variability Energy release & transport in magnetised plasma ➢ Unprecedented wavelength coverage and spatial and temporal resolution probes magnetised processes at intrinsic scales ➢ A laboratory for astrophysics Mullard Space Science Laboratory Universal Processes Solar physics is Sub-storm onset in the Earth’s about: magnetosphere • Waves (Kalmoni et al., • Instabilities 2018) • Reconnection • Turbulence & cross-scale coupling… Parameter regimes can be very different Jupiter’s but insight can be aurora (UV) (Branduardi- gained from the Raymont et study of similar al., 2008) plasma processes. Solar flare ribbons observed by the Swedish Solar Telescope. Properties of the Sun • A boring(?) middle aged star (4.5 billion years old) • In the middle of the main sequence (G2V) • Powered by fusion in the core • A magnetic star…. Courtesy University Swinburne The Sun dominates our environment • Provides heat and light • Creates solar wind, which in turn affects the Earth’s environment – from beautiful aurora – to serious disruption to satellites • Erupts with violent CMEs and flares Images from STEREO • Space is part of our environment too! Visible face of the Sun The EUV face of the Sun Sunspots Images courtesy of the Galileo Project http://galileo.rice.edu Images from Professor Owen Gingerich's copy of the first edition of Istoria e Dimo strazioni. Sunspots: sources of magnetic field SST, Royal Swedish Academy of Sciences Measuring the magnetic field Visible light: 1 March 2000 Magnetogram: 1 March 2000 The sunspot cycle Maunder Minimum NOAA/NASA prediction panel 2019 Movie courtesy of David Hathaway Rise of the Magnetic Field • Bundles of strong magnetic field rise from the base of the convection zone.
    [Show full text]
  • Solar Particle Acceleration, Radiation & Kinetics
    ESA Voyage 2050 White Paper Solar Particle Acceleration, Radiation & Kinetics (SPARK) Point of Contact: Sarah Matthews, University College London, Mullard Space Science Laboratory, Holmbury St. Mary, Dorking, Surrey, RH5 6NT, UK Email: [email protected] 5 August 2019 Executive Summary Particle acceleration is a ubiquitous process throughout the universe, observed in environments as diverse as stellar coronae, active galactic nuclei, the coronae of accretion disks around black holes, the magnetospheres of neutron stars and planetary atmospheres (including our own) interacting with the wind of their star. It operates both in very dynamic and explosive situations and in more steady phenomena where steep gradients, turbulence and instabilities exist. The product of this process, or processes, are energetic particles that fill the universe, and shape the way in which our own and other solar systems work, and what the conditions for the emergence and continuation of life might be. The Sun is a privileged place to study this fundamental astrophysical problem. It is the only astrophysical setting that allows us to probe particle acceleration by a combination of remote sensing (imaging spectroscopy) and in situ measurements, with time resolution that resolves many of the processes of acceleration and transport. This White Paper introduces a mission concept, SPARK, aimed at making significant advances in understanding particle acceleration and transport. Energetic particles are seen in nearly every manifestation of magnetic energy conversion, from large flares down to minor explosive events in active regions, and sometimes even the quiescent solar atmosphere. Several decades of hard X-ray (HXR) observations have provided substantial insights into electron acceleration, but the low energy end of the accelerated electron distribution remains poorly constrained, with profound consequences for the flare energy budget.
    [Show full text]
  • The PAC2MAN Mission: a New Tool to Understand and Predict Solar Energetic Events
    J. Space Weather Space Clim., 5, A5 (2015) DOI: 10.1051/swsc/2015005 Ó J. Amaya et al., Published by EDP Sciences 2015 EDUCATIONAL ARTICLE OPEN ACCESS The PAC2MAN mission: a new tool to understand and predict solar energetic events Jorge Amaya1,*, Sophie Musset11, Viktor Andersson2, Andrea Diercke3,4, Christian Höller5,6, Sergiu Iliev7, Lilla Juhász8, René Kiefer9, Riccardo Lasagni10, Solène Lejosne12, Mohammad Madi13, Mirko Rummelhagen14, Markus Scheucher15, Arianna Sorba16, and Stefan Thonhofer15 1 Center for mathematical Plasma-Astrophysics (CmPA), Mathematics Department, KU Leuven, Celestijnenlaan 200B, Leuven, Belgium *Corresponding author: [email protected] 2 Swedish Institute of Space Physics, Lund, Sweden 3 Leibniz-Institut für Astrophysik Potsdam (AIP), An der Sternwarte 16, 14482 Potsdam, Germany 4 Institut für Physik und Astrophysik, Universität Potsdam, 14476 Potsdam, Germany 5 Faculty of Mechanical and Industrial Engineering, University of Technology, Vienna, Austria 6 Department for Space Mechanisms, RUAG Space GmbH, Vienna, Austria 7 Aeronautical Engineering Department, Imperial College London, London, UK 8 Department of Geophysics and Space Research, Eötvös University, Budapest, Hungary 9 Kiepenheuer-Institut für Sonnenphysik (KIS), Schöneckstraße 6, 79104 Freiburg, Germany 10 Department of Aerospace Engineering, University of Bologna, Italy 11 LESIA, Observatoire de Paris, CNRS, UPMC, Universit Paris-Diderot, 5 place Jules Janssen, 92195 Meudon, France 12 British Antarctic Survey, Natural Environment Research Council, Cambridge, England, UK 13 Micos Engineering GmbH, Zürich, Switzerland 14 Berner & Mattner Systemtechnik, Munich, Germany 15 Physics Department, University of Graz, Graz, Austria 16 Blackett Laboratory, Imperial College London, London, UK Received 28 February 2014 / Accepted 2 December 2014 ABSTRACT An accurate forecast of flare and coronal mass ejection (CME) initiation requires precise measurements of the magnetic energy buildup and release in the active regions of the solar atmosphere.
    [Show full text]
  • IAU Commission 10" Solar Activity": Legacy Report and Triennial Report
    Transactions IAU, Volume XXIXA Proc. XXVIII IAU General Assembly, August 2012 c 2015 International Astronomical Union Thierry Montmerle, ed. DOI: 00.0000/X000000000000000X DIVISION II COMMISSION 10 SOLAR ACTIVITY (ACTIVITE SOLAIRE) PRESIDENT Carolus J. Schrijver VICE-PRESIDENT Lyndsay Fletcher PAST PRESIDENT Lidia van Driel-Gesztelyi ORGANIZING COMMITTEE Ayumi Asai, Paul S. Cally, Paul Charbonneau, Sarah E. Gibson, Daniel Gomez, Siraj S. Hasan, Astrid M. Veronig, Yihua Yan Abstract. After more than half a century of community support related to the science of “solar activity”, IAU’s Commission 10 was formally discontinued in 2015, to be succeeded by C.E2 with the same area of responsibility. On this occasion, we look back at the growth of the scientific disciplines involved around the world over almost a full century. Solar activity and fields of research looking into the related physics of the heliosphere continue to be vibrant and growing, with currently over 2,000 refereed publications appearing per year from over 4,000 unique authors, publishing in dozens of distinct journals and meeting in dozens of workshops and conferences each year. The size of the rapidly growing community and of the observa- tional and computational data volumes, along with the multitude of connections into other branches of astrophysics, pose significant challenges; aspects of these challenges are beginning to be addressed through, among others, the development of new systems of literature reviews, machine-searchable archives for data and publications, and virtual observatories. As customary in these reports, we highlight some of the research topics that have seen particular interest over the most recent triennium, specifically active-region magnetic fields, coronal thermal structure, coronal seismology, flares and eruptions, and the variability of solar activity on long time scales.
    [Show full text]