1
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Kasper JC, Klein KG, Lichko E, Huang J, Chen CHK, Badman ST, Bonnell J, Whittlesey PL, Livi R, Larson D, Pulupa M, Rahmati A, Stansby D, Korreck KE, Stevens M, Case AW, Bale SD, Maksimovic M, Moncuquet M, Goetz K, Halekas JS, Malaspina D, Raouafi NE, Szabo A, MacDowall R, Velli M, Dudok de Wit T, Zank GP. Parker Solar Probe Enters the Magnetically Dominated Solar Corona. Phys Rev Lett 2021; 127:255101. [PMID: 35029449 DOI: 10.1103/physrevlett.127.255101] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 11/09/2021] [Accepted: 11/15/2021] [Indexed: 06/14/2023]
Abstract
The high temperatures and strong magnetic fields of the solar corona form streams of solar wind that expand through the Solar System into interstellar space. At 09:33 UT on 28 April 2021 Parker Solar Probe entered the magnetized atmosphere of the Sun 13 million km above the photosphere, crossing below the Alfvén critical surface for five hours into plasma in casual contact with the Sun with an Alfvén Mach number of 0.79 and magnetic pressure dominating both ion and electron pressure. The spectrum of turbulence below the Alfvén critical surface is reported. Magnetic mapping suggests the region was a steady flow emerging on rapidly expanding coronal magnetic field lines lying above a pseudostreamer. The sub-Alfvénic nature of the flow may be due to suppressed magnetic reconnection at the base of the pseudostreamer, as evidenced by unusually low densities in this region and the magnetic mapping.
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Affiliation(s)
- J C Kasper
- BWX Technologies, Inc., Washington, DC 20001, USA and Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - K G Klein
- Lunar and Planetary Laboratory, University of Arizona, Tucson, Arizona 85719, USA
| | - E Lichko
- Lunar and Planetary Laboratory, University of Arizona, Tucson, Arizona 85719, USA
| | - Jia Huang
- Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - C H K Chen
- Department of Physics and Astronomy, Queen Mary University of London, London E1 4NS, United Kingdom
| | - S T Badman
- Space Sciences Laboratory at University of California, Berkeley, California, USA
| | - J Bonnell
- Space Sciences Laboratory at University of California, Berkeley, California, USA
| | - P L Whittlesey
- Space Sciences Laboratory at University of California, Berkeley, California, USA
| | - R Livi
- Space Sciences Laboratory at University of California, Berkeley, California, USA
| | - D Larson
- Space Sciences Laboratory at University of California, Berkeley, California, USA
| | - M Pulupa
- Space Sciences Laboratory at University of California, Berkeley, California, USA
| | - A Rahmati
- Space Sciences Laboratory at University of California, Berkeley, California, USA
| | - D Stansby
- Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Surrey RH5 6NT, United Kingdom
| | - K E Korreck
- Smithsonian Astrophysical Observatory, Cambridge, Massachusetts 02138, USA
| | - M Stevens
- Smithsonian Astrophysical Observatory, Cambridge, Massachusetts 02138, USA
| | - A W Case
- Smithsonian Astrophysical Observatory, Cambridge, Massachusetts 02138, USA
| | - S D Bale
- Physics Department, University of California, Berkeley, California 94720-7300, USA and Space Sciences Laboratory at University of California, Berkeley, California 94720-7300, USA
| | - M Maksimovic
- LESIA, Observatoire de Paris, Universite PSL, CNRS, Sorbonne Universite, Universite de Paris, 5 place Jules Janssen, 92195 Meudon, France
| | - M Moncuquet
- LESIA, Observatoire de Paris, Universite PSL, CNRS, Sorbonne Universite, Universite de Paris, 5 place Jules Janssen, 92195 Meudon, France
| | - K Goetz
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - J S Halekas
- Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242, USA
| | - D Malaspina
- Laboratory for Atmospheric and Space Physics, University of Colorado Boulder, Boulder, Colorado 80303, USA
| | - Nour E Raouafi
- The Johns Hopkins Applied Physics Laboratory, Laurel, Maryland 20723, USA
| | - A Szabo
- Heliospheric Physics Laboratory, NASA Goddard Space Flight Center, Greenbelt, Maryland, 20771, USA
| | - R MacDowall
- Heliospheric Physics Laboratory, NASA Goddard Space Flight Center, Greenbelt, Maryland, 20771, USA
| | - Marco Velli
- Earth Planetary and Space Sciences, UCLA, California 90095, USA
| | | | - G P Zank
- Department of Space Science and Center for Space Plasma and Aeronomic Research, University of Alabama in Huntsville, Huntsville, Alabama 35805, USA
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2
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Bowen TA, Mallet A, Bale SD, Bonnell JW, Case AW, Chandran BDG, Chasapis A, Chen CHK, Duan D, Dudok de Wit T, Goetz K, Halekas JS, Harvey PR, Kasper JC, Korreck KE, Larson D, Livi R, MacDowall RJ, Malaspina DM, McManus MD, Pulupa M, Stevens M, Whittlesey P. Constraining Ion-Scale Heating and Spectral Energy Transfer in Observations of Plasma Turbulence. Phys Rev Lett 2020; 125:025102. [PMID: 32701332 DOI: 10.1103/physrevlett.125.025102] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 05/11/2020] [Accepted: 05/22/2020] [Indexed: 06/11/2023]
Abstract
We perform a statistical study of the turbulent power spectrum at inertial and kinetic scales observed during the first perihelion encounter of the Parker Solar Probe. We find that often there is an extremely steep scaling range of the power spectrum just above the ion-kinetic scales, similar to prior observations at 1 A.U., with a power-law index of around -4. Based on our measurements, we demonstrate that either a significant (>50%) fraction of the total turbulent energy flux is dissipated in this range of scales, or the characteristic nonlinear interaction time of the turbulence decreases dramatically from the expectation based solely on the dispersive nature of nonlinearly interacting kinetic Alfvén waves.
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Affiliation(s)
- Trevor A Bowen
- Space Sciences Laboratory, University of California, Berkeley, California 94720-7450, USA
| | - Alfred Mallet
- Space Sciences Laboratory, University of California, Berkeley, California 94720-7450, USA
| | - Stuart D Bale
- Space Sciences Laboratory, University of California, Berkeley, California 94720-7450, USA
- Physics Department, University of California, Berkeley, California 94720-7300, USA
- The Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
- School of Physics and Astronomy, Queen Mary University of London, London E1 4NS, United Kingdom
| | - J W Bonnell
- Space Sciences Laboratory, University of California, Berkeley, California 94720-7450, USA
| | - Anthony W Case
- Smithsonian Astrophysical Observatory, Cambridge, Massachusetts 02138, USA
| | - Benjamin D G Chandran
- Department of Physics and Astronomy, University of New Hampshire, Durham, New Hampshire 03824, USA
- Space Science Center, University of New Hampshire, Durham, New Hampshire 03824, USA
| | - Alexandros Chasapis
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80303, USA
| | - Christopher H K Chen
- School of Physics and Astronomy, Queen Mary University of London, London E1 4NS, United Kingdom
| | - Die Duan
- Space Sciences Laboratory, University of California, Berkeley, California 94720-7450, USA
- School of Earth and Space Sciences, Peking University, Beijing 100871, China
| | - Thierry Dudok de Wit
- LPC2E, CNRS and University of Orléans, 3 Avenue de la Recherche Scientifique, 45071 Orléans, France
| | - Keith Goetz
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Jasper S Halekas
- Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242, USA
| | - Peter R Harvey
- Space Sciences Laboratory, University of California, Berkeley, California 94720-7450, USA
| | - J C Kasper
- Smithsonian Astrophysical Observatory, Cambridge, Massachusetts 02138, USA
- Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Kelly E Korreck
- Smithsonian Astrophysical Observatory, Cambridge, Massachusetts 02138, USA
| | - Davin Larson
- Space Sciences Laboratory, University of California, Berkeley, California 94720-7450, USA
| | - Roberto Livi
- Space Sciences Laboratory, University of California, Berkeley, California 94720-7450, USA
| | - Robert J MacDowall
- Solar System Exploration Division, NASA/Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - David M Malaspina
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80303, USA
- Astrophysical and Planetary Sciences Department, University of Colorado, Boulder, Colorado, USA
| | - Michael D McManus
- Space Sciences Laboratory, University of California, Berkeley, California 94720-7450, USA
- Physics Department, University of California, Berkeley, California 94720-7300, USA
| | - Marc Pulupa
- Space Sciences Laboratory, University of California, Berkeley, California 94720-7450, USA
| | - Michael Stevens
- Smithsonian Astrophysical Observatory, Cambridge, Massachusetts 02138, USA
| | - Phyllis Whittlesey
- Space Sciences Laboratory, University of California, Berkeley, California 94720-7450, USA
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3
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Kasper JC, Bale SD, Belcher JW, Berthomier M, Case AW, Chandran BDG, Curtis DW, Gallagher D, Gary SP, Golub L, Halekas JS, Ho GC, Horbury TS, Hu Q, Huang J, Klein KG, Korreck KE, Larson DE, Livi R, Maruca B, Lavraud B, Louarn P, Maksimovic M, Martinovic M, McGinnis D, Pogorelov NV, Richardson JD, Skoug RM, Steinberg JT, Stevens ML, Szabo A, Velli M, Whittlesey PL, Wright KH, Zank GP, MacDowall RJ, McComas DJ, McNutt RL, Pulupa M, Raouafi NE, Schwadron NA. Alfvénic velocity spikes and rotational flows in the near-Sun solar wind. Nature 2019; 576:228-231. [PMID: 31802006 DOI: 10.1038/s41586-019-1813-z] [Citation(s) in RCA: 216] [Impact Index Per Article: 43.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 10/17/2019] [Indexed: 11/09/2022]
Abstract
The prediction of a supersonic solar wind1 was first confirmed by spacecraft near Earth2,3 and later by spacecraft at heliocentric distances as small as 62 solar radii4. These missions showed that plasma accelerates as it emerges from the corona, aided by unidentified processes that transport energy outwards from the Sun before depositing it in the wind. Alfvénic fluctuations are a promising candidate for such a process because they are seen in the corona and solar wind and contain considerable energy5-7. Magnetic tension forces the corona to co-rotate with the Sun, but any residual rotation far from the Sun reported until now has been much smaller than the amplitude of waves and deflections from interacting wind streams8. Here we report observations of solar-wind plasma at heliocentric distances of about 35 solar radii9-11, well within the distance at which stream interactions become important. We find that Alfvén waves organize into structured velocity spikes with duration of up to minutes, which are associated with propagating S-like bends in the magnetic-field lines. We detect an increasing rotational component to the flow velocity of the solar wind around the Sun, peaking at 35 to 50 kilometres per second-considerably above the amplitude of the waves. These flows exceed classical velocity predictions of a few kilometres per second, challenging models of circulation in the corona and calling into question our understanding of how stars lose angular momentum and spin down as they age12-14.
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Affiliation(s)
- J C Kasper
- Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI, USA. .,Smithsonian Astrophysical Observatory, Cambridge, MA, USA.
| | - S D Bale
- Physics Department, University of California, Berkeley, CA, USA.,Space Sciences Laboratory, University of California, Berkeley, CA, USA.,The Blackett Laboratory, Imperial College London, London, UK
| | - J W Belcher
- Kavli Center for Astrophysics and Space Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - M Berthomier
- Laboratoire de Physique des Plasmas, CNRS, Sorbonne Université, Ecole Polytechnique, Observatoire de Paris, Université Paris-Saclay, Paris, France
| | - A W Case
- Smithsonian Astrophysical Observatory, Cambridge, MA, USA
| | - B D G Chandran
- Department of Physics and Astronomy, University of New Hampshire, Durham, NH, USA.,Space Science Center, University of New Hampshire, Durham, NH, USA
| | - D W Curtis
- Space Sciences Laboratory, University of California, Berkeley, CA, USA
| | - D Gallagher
- Heliophysics and Planetary Science Branch ST13, Marshall Space Flight Center, Huntsville, AL, USA
| | - S P Gary
- Los Alamos National Laboratory, Los Alamos, NM, USA
| | - L Golub
- Smithsonian Astrophysical Observatory, Cambridge, MA, USA
| | - J S Halekas
- Department of Physics and Astronomy, University of Iowa, IA, USA
| | - G C Ho
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - T S Horbury
- The Blackett Laboratory, Imperial College London, London, UK
| | - Q Hu
- Department of Space Science and Center for Space Plasma and Aeronomic Research, University of Alabama in Huntsville, Huntsville, AL, USA
| | - J Huang
- Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI, USA
| | - K G Klein
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA.,Department of Planetary Sciences, University of Arizona, Tucson, AZ, USA
| | - K E Korreck
- Smithsonian Astrophysical Observatory, Cambridge, MA, USA
| | - D E Larson
- Space Sciences Laboratory, University of California, Berkeley, CA, USA
| | - R Livi
- Space Sciences Laboratory, University of California, Berkeley, CA, USA
| | - B Maruca
- Department of Physics and Astronomy, University of Delaware, Newark, DE, USA.,Bartol Research Institute, University of Delaware, Newark, DE, USA
| | - B Lavraud
- Institut de Recherche en Astrophysique et Planétologie, CNRS, UPS, CNES, Université de Toulouse, Toulouse, France
| | - P Louarn
- Institut de Recherche en Astrophysique et Planétologie, CNRS, UPS, CNES, Université de Toulouse, Toulouse, France
| | - M Maksimovic
- LESIA, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Université de Paris, Meudon, France
| | - M Martinovic
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - D McGinnis
- Department of Physics and Astronomy, University of Iowa, IA, USA
| | - N V Pogorelov
- Department of Space Science and Center for Space Plasma and Aeronomic Research, University of Alabama in Huntsville, Huntsville, AL, USA
| | - J D Richardson
- Kavli Center for Astrophysics and Space Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - R M Skoug
- Los Alamos National Laboratory, Los Alamos, NM, USA
| | | | - M L Stevens
- Smithsonian Astrophysical Observatory, Cambridge, MA, USA
| | - A Szabo
- NASA/Goddard Space Flight Center, Greenbelt, MD, USA
| | - M Velli
- Department of Earth, Planetary and Space Sciences, University of California, Los Angeles, CA, USA
| | - P L Whittlesey
- Space Sciences Laboratory, University of California, Berkeley, CA, USA
| | - K H Wright
- Universities Space Research Association, Science and Technology Institute, Huntsville, AL, USA
| | - G P Zank
- Department of Space Science and Center for Space Plasma and Aeronomic Research, University of Alabama in Huntsville, Huntsville, AL, USA
| | - R J MacDowall
- NASA/Goddard Space Flight Center, Greenbelt, MD, USA
| | - D J McComas
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ, USA
| | - R L McNutt
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - M Pulupa
- Space Sciences Laboratory, University of California, Berkeley, CA, USA
| | - N E Raouafi
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - N A Schwadron
- Department of Physics and Astronomy, University of New Hampshire, Durham, NH, USA.,Space Science Center, University of New Hampshire, Durham, NH, USA
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4
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McComas DJ, Christian ER, Cohen CMS, Cummings AC, Davis AJ, Desai MI, Giacalone J, Hill ME, Joyce CJ, Krimigis SM, Labrador AW, Leske RA, Malandraki O, Matthaeus WH, McNutt RL, Mewaldt RA, Mitchell DG, Posner A, Rankin JS, Roelof EC, Schwadron NA, Stone EC, Szalay JR, Wiedenbeck ME, Bale SD, Kasper JC, Case AW, Korreck KE, MacDowall RJ, Pulupa M, Stevens ML, Rouillard AP. Probing the energetic particle environment near the Sun. Nature 2019; 576:223-227. [PMID: 31802005 PMCID: PMC6908744 DOI: 10.1038/s41586-019-1811-1] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 09/05/2019] [Indexed: 11/18/2022]
Abstract
NASA's Parker Solar Probe mission1 recently plunged through the inner heliosphere of the Sun to its perihelia, about 24 million kilometres from the Sun. Previous studies farther from the Sun (performed mostly at a distance of 1 astronomical unit) indicate that solar energetic particles are accelerated from a few kiloelectronvolts up to near-relativistic energies via at least two processes: 'impulsive' events, which are usually associated with magnetic reconnection in solar flares and are typically enriched in electrons, helium-3 and heavier ions2, and 'gradual' events3,4, which are typically associated with large coronal-mass-ejection-driven shocks and compressions moving through the corona and inner solar wind and are the dominant source of protons with energies between 1 and 10 megaelectronvolts. However, some events show aspects of both processes and the electron-proton ratio is not bimodally distributed, as would be expected if there were only two possible processes5. These processes have been very difficult to resolve from prior observations, owing to the various transport effects that affect the energetic particle population en route to more distant spacecraft6. Here we report observations of the near-Sun energetic particle radiation environment over the first two orbits of the probe. We find a variety of energetic particle events accelerated both locally and remotely including by corotating interaction regions, impulsive events driven by acceleration near the Sun, and an event related to a coronal mass ejection. We provide direct observations of the energetic particle radiation environment in the region just above the corona of the Sun and directly explore the physics of particle acceleration and transport.
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Affiliation(s)
- D J McComas
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ, USA.
| | | | - C M S Cohen
- California Institute of Technology, Pasadena, CA, USA
| | - A C Cummings
- California Institute of Technology, Pasadena, CA, USA
| | - A J Davis
- California Institute of Technology, Pasadena, CA, USA
| | - M I Desai
- Southwest Research Institute, San Antonio, TX, USA
- University of Texas at San Antonio, San Antonio, TX, USA
| | | | - M E Hill
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - C J Joyce
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ, USA
| | - S M Krimigis
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - A W Labrador
- California Institute of Technology, Pasadena, CA, USA
| | - R A Leske
- California Institute of Technology, Pasadena, CA, USA
| | - O Malandraki
- National Observatory of Athens, IAASARS, Athens, Greece
| | | | - R L McNutt
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - R A Mewaldt
- California Institute of Technology, Pasadena, CA, USA
| | - D G Mitchell
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | | | - J S Rankin
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ, USA
| | - E C Roelof
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - N A Schwadron
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ, USA
- University of New Hampshire, Durham, NH, USA
| | - E C Stone
- California Institute of Technology, Pasadena, CA, USA
| | - J R Szalay
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ, USA
| | - M E Wiedenbeck
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - S D Bale
- University of California at Berkeley, Berkeley, CA, USA
- The Blackett Laboratory, Imperial College London, London, UK
| | - J C Kasper
- University of Michigan, Ann Arbor, MI, USA
| | - A W Case
- Smithsonian Astrophysical Observatory, Cambridge, MA, USA
| | - K E Korreck
- Smithsonian Astrophysical Observatory, Cambridge, MA, USA
| | | | - M Pulupa
- University of California at Berkeley, Berkeley, CA, USA
| | - M L Stevens
- Smithsonian Astrophysical Observatory, Cambridge, MA, USA
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5
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Cirtain JW, Golub L, Winebarger AR, De Pontieu B, Kobayashi K, Moore RL, Walsh RW, Korreck KE, Weber M, McCauley P, Title A, Kuzin S, DeForest CE. Energy release in the solar corona from spatially resolved magnetic braids. Nature 2013; 493:501-3. [PMID: 23344359 DOI: 10.1038/nature11772] [Citation(s) in RCA: 213] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Accepted: 11/01/2012] [Indexed: 11/09/2022]
Abstract
It is now apparent that there are at least two heating mechanisms in the Sun's outer atmosphere, or corona. Wave heating may be the prevalent mechanism in quiet solar periods and may contribute to heating the corona to 1,500,000 K (refs 1-3). The active corona needs additional heating to reach 2,000,000-4,000,000 K; this heat has been theoretically proposed to come from the reconnection and unravelling of magnetic 'braids'. Evidence favouring that process has been inferred, but has not been generally accepted because observations are sparse and, in general, the braided magnetic strands that are thought to have an angular width of about 0.2 arc seconds have not been resolved. Fine-scale braiding has been seen in the chromosphere but not, until now, in the corona. Here we report observations, at a resolution of 0.2 arc seconds, of magnetic braids in a coronal active region that are reconnecting, relaxing and dissipating sufficient energy to heat the structures to about 4,000,000 K. Although our 5-minute observations cannot unambiguously identify the field reconnection and subsequent relaxation as the dominant heating mechanism throughout active regions, the energy available from the observed field relaxation in our example is ample for the observed heating.
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Affiliation(s)
- J W Cirtain
- Marshall Space Flight Center, NASA, Mail Code ZP13, MSFC, Alabama 36812, USA.
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6
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Sakao T, Kano R, Narukage N, Kotoku J, Bando T, Deluca EE, Lundquist LL, Tsuneta S, Harra LK, Katsukawa Y, Kubo M, Hara H, Matsuzaki K, Shimojo M, Bookbinder JA, Golub L, Korreck KE, Su Y, Shibasaki K, Shimizu T, Nakatani I. Continuous plasma outflows from the edge of a solar active region as a possible source of solar wind. Science 2007; 318:1585-8. [PMID: 18063788 DOI: 10.1126/science.1147292] [Citation(s) in RCA: 164] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The Sun continuously expels a huge amount of ionized material into interplanetary space as the solar wind. Despite its influence on the heliospheric environment, the origin of the solar wind has yet to be well identified. In this paper, we report Hinode X-ray Telescope observations of a solar active region. At the edge of the active region, located adjacent to a coronal hole, a pattern of continuous outflow of soft-x-ray-emitting plasmas was identified emanating along apparently open magnetic field lines and into the upper corona. Estimates of temperature and density for the outflowing plasmas suggest a mass loss rate that amounts to approximately 1/4 of the total mass loss rate of the solar wind. These outflows may be indicative of one of the solar wind sources at the Sun.
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Affiliation(s)
- Taro Sakao
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510, Japan.
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