A series of plasma flow vortices in the tail plasma sheet associated with solar wind pressure enhancement

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Zeitschriftentitel:	Journal of Geophysical Research: Space Physics
Personen und Körperschaften:	Tian, A. M., Zong, Q. G., Wang, Y. F., Shi, Q. Q., Fu, S. Y., Pu, Z. Y.
In:	Journal of Geophysical Research: Space Physics, 115, 2010, A9
Format:	E-Article
Sprache:	Englisch
veröffentlicht:	American Geophysical Union (AGU)
Schlagwörter:	Paleontology Space and Planetary Science Earth and Planetary Sciences (miscellaneous) Atmospheric Science Earth-Surface Processes Geochemistry and Petrology Soil Science Water Science and Technology Ecology Aquatic Science Forestry Oceanography Geophysics

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Zusammenfassung:	<jats:p>A series of earthward‐moving (∼140 km/s) plasma flow vortices with anticlockwise (when viewed from above the ecliptic plane) rotation was detected in the dawnside tail plasma sheet between 1255 and 1400 UT on 6 July 2003. These flow vortices were observed under the condition of northward interplanetary magnetic field with an enhanced solar wind dynamic pressure. Analysing the plasma and magnetic field data from the Cluster spacecraft and using the Grad‐Shafranov streamline reconstruction technique, we show that the vortex‐like plasma structures have a very similar shape: a <jats:italic>V</jats:italic><jats:sub><jats:italic>x</jats:italic></jats:sub> component dominant in the dawnside, while a distinct <jats:italic>V</jats:italic><jats:sub><jats:italic>y</jats:italic></jats:sub> component appears in the duskside, and each structure has a size of about 1.8 × 0.68 <jats:italic>R</jats:italic><jats:sub><jats:italic>E</jats:italic></jats:sub>, approximately in the <jats:italic>xy</jats:italic> plane of GSM coordinates. It is found that the vortices contain both magnetosphere‐originated hot (<jats:italic>N</jats:italic> ∼ 0.1 cm<jats:sup>−3</jats:sup>, <jats:italic>E</jats:italic> > 3 keV) and magnetosheath‐originated denser and colder (<jats:italic>N</jats:italic> > 0.2 cm<jats:sup>−3</jats:sup>, <jats:italic>E</jats:italic> < 1 keV) populations on the closed field lines. The vortices involve fast earthward flows (<jats:italic>V</jats:italic><jats:sub><jats:italic>x</jats:italic></jats:sub> > 200 km/s) of mainly sheath‐originated plasmas. We suggest that these observed plasma flow vortices are generated inside the magnetotail during the prolonged and intensified compression of the magnetosphere by the enhanced solar wind dynamic pressure.</jats:p>
ISSN:	0148-0227
DOI:	10.1029/2009ja014989