Alfvénic velocity spikes and rotational flows in the near-Sun solar wind

J C Kasper^{1

2}, S D Bale^{3

4

5}, J W Belcher⁶, M Berthomier⁷, A W Case⁸, B D G Chandran^{9

10}, D W Curtis⁴, D Gallagher¹¹, S P Gary¹², L Golub⁸, J S Halekas¹³, G C Ho¹⁴, T S Horbury⁵, Q Hu¹⁵, J Huang¹⁶, K G Klein^{17

18}, K E Korreck⁸, D E Larson⁴, R Livi⁴, B Maruca^{19

20}, B Lavraud²¹, P Louarn²¹, M Maksimovic²², M Martinovic¹⁷, D McGinnis¹³, N V Pogorelov¹⁵, J D Richardson⁶, R M Skoug¹², J T Steinberg¹², M L Stevens⁸, A Szabo²³, M Velli²⁴, P L Whittlesey⁴, K H Wright²⁵, G P Zank¹⁵, R J MacDowall²³, D J McComas²⁶, R L McNutt Jr¹⁴, M Pulupa⁴, N E Raouafi¹⁴, N A Schwadron^{9

10}

Affiliations

¹ Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI, USA. jckasper@umich.edu.
² Smithsonian Astrophysical Observatory, Cambridge, MA, USA. jckasper@umich.edu.
³ Physics Department, University of California, Berkeley, CA, USA.
⁴ Space Sciences Laboratory, University of California, Berkeley, CA, USA.
⁵ The Blackett Laboratory, Imperial College London, London, UK.
⁶ Kavli Center for Astrophysics and Space Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA.
⁷ Laboratoire de Physique des Plasmas, CNRS, Sorbonne Université, Ecole Polytechnique, Observatoire de Paris, Université Paris-Saclay, Paris, France.
⁸ Smithsonian Astrophysical Observatory, Cambridge, MA, USA.
⁹ Department of Physics and Astronomy, University of New Hampshire, Durham, NH, USA.
¹⁰ Space Science Center, University of New Hampshire, Durham, NH, USA.
¹¹ Heliophysics and Planetary Science Branch ST13, Marshall Space Flight Center, Huntsville, AL, USA.
¹² Los Alamos National Laboratory, Los Alamos, NM, USA.
¹³ Department of Physics and Astronomy, University of Iowa, IA, USA.
¹⁴ Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA.
¹⁵ Department of Space Science and Center for Space Plasma and Aeronomic Research, University of Alabama in Huntsville, Huntsville, AL, USA.
¹⁶ Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI, USA.
¹⁷ Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA.
¹⁸ Department of Planetary Sciences, University of Arizona, Tucson, AZ, USA.
¹⁹ Department of Physics and Astronomy, University of Delaware, Newark, DE, USA.
²⁰ Bartol Research Institute, University of Delaware, Newark, DE, USA.
²¹ Institut de Recherche en Astrophysique et Planétologie, CNRS, UPS, CNES, Université de Toulouse, Toulouse, France.
²² LESIA, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Université de Paris, Meudon, France.
²³ NASA/Goddard Space Flight Center, Greenbelt, MD, USA.
²⁴ Department of Earth, Planetary and Space Sciences, University of California, Los Angeles, CA, USA.
²⁵ Universities Space Research Association, Science and Technology Institute, Huntsville, AL, USA.
²⁶ Department of Astrophysical Sciences, Princeton University, Princeton, NJ, USA.

PMID: 31802006
DOI: 10.1038/s41586-019-1813-z

Alfvénic velocity spikes and rotational flows in the near-Sun solar wind

J C Kasper et al. Nature. 2019 Dec.

. 2019 Dec;576(7786):228-231.

doi: 10.1038/s41586-019-1813-z. Epub 2019 Dec 4.

Authors

Affiliations

¹ Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI, USA. jckasper@umich.edu.
² Smithsonian Astrophysical Observatory, Cambridge, MA, USA. jckasper@umich.edu.
³ Physics Department, University of California, Berkeley, CA, USA.
⁴ Space Sciences Laboratory, University of California, Berkeley, CA, USA.
⁵ The Blackett Laboratory, Imperial College London, London, UK.
⁶ Kavli Center for Astrophysics and Space Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA.
⁷ Laboratoire de Physique des Plasmas, CNRS, Sorbonne Université, Ecole Polytechnique, Observatoire de Paris, Université Paris-Saclay, Paris, France.
⁸ Smithsonian Astrophysical Observatory, Cambridge, MA, USA.
⁹ Department of Physics and Astronomy, University of New Hampshire, Durham, NH, USA.
¹⁰ Space Science Center, University of New Hampshire, Durham, NH, USA.
¹¹ Heliophysics and Planetary Science Branch ST13, Marshall Space Flight Center, Huntsville, AL, USA.
¹² Los Alamos National Laboratory, Los Alamos, NM, USA.
¹³ Department of Physics and Astronomy, University of Iowa, IA, USA.
¹⁴ Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA.
¹⁵ Department of Space Science and Center for Space Plasma and Aeronomic Research, University of Alabama in Huntsville, Huntsville, AL, USA.
¹⁶ Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI, USA.
¹⁷ Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA.
¹⁸ Department of Planetary Sciences, University of Arizona, Tucson, AZ, USA.
¹⁹ Department of Physics and Astronomy, University of Delaware, Newark, DE, USA.
²⁰ Bartol Research Institute, University of Delaware, Newark, DE, USA.
²¹ Institut de Recherche en Astrophysique et Planétologie, CNRS, UPS, CNES, Université de Toulouse, Toulouse, France.
²² LESIA, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Université de Paris, Meudon, France.
²³ NASA/Goddard Space Flight Center, Greenbelt, MD, USA.
²⁴ Department of Earth, Planetary and Space Sciences, University of California, Los Angeles, CA, USA.
²⁵ Universities Space Research Association, Science and Technology Institute, Huntsville, AL, USA.
²⁶ Department of Astrophysical Sciences, Princeton University, Princeton, NJ, USA.

PMID: 31802006
DOI: 10.1038/s41586-019-1813-z

Abstract

The prediction of a supersonic solar wind¹ was first confirmed by spacecraft near Earth^2,3 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 energy^5-7. 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 radii^9-11, 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 age^12-14.

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Comment in

Sun-bombing spacecraft uncovers secrets of the solar wind.
Witze A. Witze A. Nature. 2019 Dec;576(7785):15-16. doi: 10.1038/d41586-019-03684-0. Nature. 2019. PMID: 31802020 No abstract available.
A step closer to the Sun's secrets.
Verscharen D. Verscharen D. Nature. 2019 Dec;576(7786):219-220. doi: 10.1038/d41586-019-03665-3. Nature. 2019. PMID: 31822830 No abstract available.

References

1. Parker, E. N. Dynamics of the interplanetary gas and magnetic fields. Astrophys. J. 128, 664–676 (1958). - DOI
1. Gringauz, K. I., Bezrokikh, V. V., Ozerov, V. D. & Rybchinskii, R. E. A study of the interplanetary ionized gas, high-energy electrons and corpuscular radiation from the Sun by means of the three-electrode trap for charged particles on the second Soviet cosmic rocket. Sov. Phys. Dokl. 5, 361–364 (1960).
1. Bonetti, A., Bridge, H. S., Lazarus, A. J., Rossi, B. & Scherb, F. Explorer 10 plasma measurements. J. Geophys. Res. 68, 4017–4063 (1963). - DOI
1. Marsch, E. et al. Solar wind protons – three-dimensional velocity distributions and derived plasma parameters measured between 0.3 and 1 AU. J. Geophys. Res. 87, 52–72 (1982). - DOI
1. Belcher, J. W. & Davis, L. Jr Large-amplitude Alfvén waves in the interplanetary medium, 2. J. Geophys. Res. 76, 3534–3563 (1971). - DOI

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Alfvénic velocity spikes and rotational flows in the near-Sun solar wind

Affiliations

Alfvénic velocity spikes and rotational flows in the near-Sun solar wind

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Affiliations

Abstract

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