Journal article
Alfvénic Velocity Spikes and Rotational Flows in the Near-Sun Solar Wind
Nature (London), Vol.576(7786), pp.228-231
12/12/2019
DOI: 10.1038/s41586-019-1813-z
PMID: 31802006
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.
Details
- Title: Subtitle
- Alfvénic Velocity Spikes and Rotational Flows in the Near-Sun Solar Wind
- Creators
- Justin C. Kasper - University of MichiganStuart D. Bale - University of California, BerkeleyJohn W. Belcher - Massachusetts Institute of TechnologyMatthieu Berthomier - École PolytechniqueAnthony W. Case - Smithsonian Astrophysical ObservatoryBenjamin D. G. Chandran - University of New Hampshire at ManchesterD.W. Curtis - University of California, BerkeleyD. Gallagher - Marshall Space Flight CenterS.P. Gary - Los Alamos National LaboratoryL. Golub - Smithsonian Astrophysical ObservatoryJasper S. Halekas - University of IowaGeorges Ho - Johns Hopkins University Applied Physics LaboratoryT.S. Horbury - Imperial College LondonQ. Hu - University of Alabama in HuntsvilleJ. Huang - University of MichiganKristopher G. KleinKelly E. Korreck - Smithsonian Astrophysical ObservatoryDavin Larson - University of California, BerkeleyRoberto Livi - University of California, BerkeleyBennett Maruca - University of DelawareBenoit Lavraud - Université Fédérale de Toulouse Midi-PyrénéesPhilippe Louarn - Université Fédérale de Toulouse Midi-PyrénéesMilan Maksimovic - Université Paris CitéMihailo Martinović - University of ArizonaD. Mcginnis - University of IowaN. V. Pogorelov - University of Alabama in HuntsvilleJ.D. Richardson - Massachusetts Institute of TechnologyR. M. Skoug - Los Alamos National LaboratoryJ.T. Steinberg - Los Alamos National LaboratoryMichael L. Stevens - Smithsonian Astrophysical ObservatoryAdam Szabo - Goddard Space Flight CenterPhyllis Whittlesey - University of California, BerkeleyMarco Velli - University of California, Los AngelesK. Wright - Universities Space Research AssociationGary P. Zank - University of Alabama in HuntsvilleR.J Macdowall - Goddard Space Flight CenterDavid J. Mccomas - Princeton UniversityRalph Mcnutt - Johns Hopkins University Applied Physics LaboratoryMarc Pulupa - University of California, BerkeleyNoureddine Raouafi - Johns Hopkins University Applied Physics LaboratoryNathan A. Schwadron - University of New Hampshire
- Resource Type
- Journal article
- Publication Details
- Nature (London), Vol.576(7786), pp.228-231
- DOI
- 10.1038/s41586-019-1813-z
- PMID
- 31802006
- NLM abbreviation
- Nature
- ISSN
- 0028-0836
- eISSN
- 1476-4687
- Publisher
- Nature Publishing Group
- Language
- English
- Date published
- 12/12/2019
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984428771002771
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