Spatial distribution of rolled up Kelvin-Helmholtz vortices at Earth’s dayside and flank magnetopause

نویسندگان

  • M. G. G. T. Taylor
  • H. Hasegawa
  • B. Lavraud
  • T. Phan
  • C. P. Escoubet
  • M. W. Dunlop
  • Y. V. Bogdanova
  • A. L. Borg
  • M. Volwerk
  • J. Berchem
  • O. D. Constantinescu
  • J. P. Eastwood
  • A. Masson
  • H. Laakso
  • J. Soucek
  • A. N. Fazakerley
  • H. U. Frey
  • E. V. Panov
  • C. Shen
  • J. K. Shi
  • D. G. Sibeck
  • Z. Y. Pu
  • J. Wang
  • J. A. Wild
چکیده

The Kelvin-Helmholtz Instability (KHI) can drive waves at the magnetopause. These waves can grow to form rolled-up vortices and facilitate transfer of plasma into the magnetosphere. To investigate the persistence and frequency of such waves at the magnetopause we have carried out a survey of all Double Star 1 magnetopause crossings, using a combination of ion and magnetic field measurements. Using criteria originally used in a Geotail study made by Hasegawa et al. (2006) (forthwith referred to as H2006), 17 candidate events were identified from the entire TC-1 mission (covering ∼623 orbits where the magnetopause was sampled), a majority of which were on the dayside of the terminator. The relationship between density and shear velocity was then investigated, to identify the predicted signature of a rolled up vortex from H2006 and all 17 events exhibited some level of rolled up behavior. The location of the events had a clear dawn-dusk asymmetry, with 12 (71 %) on the post noon, dusk flank suggesting preferential growth in this region.

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تاریخ انتشار 2012