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Sökning: onr:"swepub:oai:DiVA.org:uu-414322" > Generation of Turbu...

LIBRIS Formathandbok  (Information om MARC21)
FältnamnIndikatorerMetadata
00005667naa a2200421 4500
001oai:DiVA.org:uu-414322
003SwePub
008200625s2020 | |||||||||||000 ||eng|
0247 a https://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4143222 URI
0247 a https://doi.org/10.1029/2019JA0275952 DOI
040 a (SwePub)uu
041 a engb eng
042 9 SwePub
072 7a ref2 swepub-contenttype
072 7a art2 swepub-publicationtype
1001 a Hasegawa, H.u Japan Aerosp Explorat Agcy, Inst Space & Astronaut Sci, Sagamihara, Kanagawa, Japan.4 aut
2451 0a Generation of Turbulence in Kelvin-Helmholtz Vortices at the Earth's Magnetopause :b Magnetospheric Multiscale Observations
264 1c 2020
338 a print2 rdacarrier
520 a The Kelvin-Helmholtz instability (KHI) at Earth's magnetopause and associated turbulence are suggested to play a role in the transport of mass and momentum from the solar wind into Earth's magnetosphere. We investigate electromagnetic turbulence observed in Kelvin-Helmholtz vortices encountered at the dusk flank magnetopause by the Magnetospheric Multiscale (MMS) spacecraft under northward interplanetary magnetic field (IMF) conditions in order to reveal its generation process, mode properties, and role. A comparison with another MMS event at the dayside magnetopause with reconnection but no KHI signatures under a similar IMF condition indicates that while high-latitude magnetopause reconnection excites a modest level of turbulence in the dayside low-latitude boundary layer, the KHI further amplifies the turbulence, leading to magnetic energy spectra with a power law index -5/3 at magnetohydrodynamic scales even in its early nonlinear phase. The mode of the electromagnetic turbulence is analyzed with a single-spacecraft method based on Ampere's law, developed by Bellan (2016, https://doi.org/10.1002/2016JA022827), for estimating wave vectors as a function of spacecraft frame frequency. The results suggest that the turbulence does not consist of propagating normal-mode waves but is due to interlaced magnetic flux tubes advected by plasma flows in the vortices. The turbulence at sub-ion scales in the early nonlinear phase of the KHI may not be the cause of the plasma transport across the magnetopause but rather a consequence of three-dimensional vortex-induced reconnection, the process that can cause an efficient transport by producing tangled reconnected field lines. Plain Language Summary Turbulence is ubiquitous in nature and plays an important role in material mixing and energy transport. Turbulence in space plasmas is characterized by fluctuations of flow velocity and/or electromagnetic fields over a broad frequency range and/or length scales and is believed to be the key to efficient plasma transport and heating. However, its generation mechanism is not fully understood because turbulence in space is often fully developed or already relaxed when observed. By analyzing high-resolution plasma and electromagnetic field data taken by the Magnetospheric Multiscale spacecraft, we study the generation process of electromagnetic turbulence at the outer boundary of Earth's magnetosphere, called the magnetopause, where either a flow shear-driven Kelvin-Helmholtz instability or magnetic reconnection or both could drive turbulence. It is shown that while dayside reconnection generates a modest level of turbulence at the magnetopause near noon, the flow shear instability further amplifies the turbulence at the flank magnetopause. Our analysis also suggests that the turbulence may not be the primary cause of plasma transport from solar wind into the magnetosphere but rather a consequence of the flow shear-induced reconnection that is likely the primary cause of plasma transport at the dayside flank under northward solar wind magnetic field conditions.
650 7a NATURVETENSKAPx Fysikx Fusion, plasma och rymdfysik0 (SwePub)103032 hsv//swe
650 7a NATURAL SCIENCESx Physical Sciencesx Fusion, Plasma and Space Physics0 (SwePub)103032 hsv//eng
650 7a NATURVETENSKAPx Fysikx Astronomi, astrofysik och kosmologi0 (SwePub)103052 hsv//swe
650 7a NATURAL SCIENCESx Physical Sciencesx Astronomy, Astrophysics and Cosmology0 (SwePub)103052 hsv//eng
7001 a Nakamura, T. K. M.u Austrian Acad Sci, Space Res Inst, Graz, Austria.4 aut
7001 a Gershman, D. J.u NASA, Goddard Space Flight Ctr, Greenbelt, MD USA.4 aut
7001 a Nariyuki, Y.u Toyama Univ, Fac Human Dev, Toyama, Japan.4 aut
7001 a Vinas, A. F.u NASA, Goddard Space Flight Ctr, Greenbelt, MD USA.4 aut
7001 a Giles, B. L.u NASA, Goddard Space Flight Ctr, Greenbelt, MD USA.4 aut
7001 a Lavraud, B.u Univ Toulouse, CNRS, Inst Rech Astrophys & Planetol, UPS, Toulouse, France.4 aut
7001 a Russell, C. T.u Univ Calif Los Angeles, Dept Earth Planetary & Space Sci, Los Angeles, CA USA.4 aut
7001 a Khotyaintsev, Yuri V.u Uppsala universitet,Institutet för rymdfysik, Uppsalaavdelningen4 aut0 (Swepub:uu)ykh28990
7001 a Ergun, R. E.u Univ Colorado, Dept Astrophys & Planetary Sci, Boulder, CO 80309 USA.4 aut
7001 a Saito, Y.u Japan Aerosp Explorat Agcy, Inst Space & Astronaut Sci, Sagamihara, Kanagawa, Japan.4 aut
7102 a Japan Aerosp Explorat Agcy, Inst Space & Astronaut Sci, Sagamihara, Kanagawa, Japan.b Austrian Acad Sci, Space Res Inst, Graz, Austria.4 org
7730 t Journal of Geophysical Research - Space Physicsg 125:3q 125:3x 2169-9380x 2169-9402
8564 8u https://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-414322
8564 8u https://doi.org/10.1029/2019JA027595

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