Journal cover Journal topic
Annales Geophysicae An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

Journal metrics

  • IF value: 1.490 IF 1.490
  • IF 5-year value: 1.445 IF 5-year
    1.445
  • CiteScore value: 2.9 CiteScore
    2.9
  • SNIP value: 0.789 SNIP 0.789
  • IPP value: 1.48 IPP 1.48
  • SJR value: 0.74 SJR 0.74
  • Scimago H <br class='hide-on-tablet hide-on-mobile'>index value: 88 Scimago H
    index 88
  • h5-index value: 21 h5-index 21
Volume 26, issue 6
Ann. Geophys., 26, 1559–1566, 2008
https://doi.org/10.5194/angeo-26-1559-2008
© Author(s) 2008. This work is distributed under
the Creative Commons Attribution 3.0 License.
Ann. Geophys., 26, 1559–1566, 2008
https://doi.org/10.5194/angeo-26-1559-2008
© Author(s) 2008. This work is distributed under
the Creative Commons Attribution 3.0 License.

  11 Jun 2008

11 Jun 2008

Observation of three distinct ion populations at the Kelvin-Helmholtz-unstable magnetopause

M. G. G. T. Taylor1 and B. Lavraud2,* M. G. G. T. Taylor and B. Lavraud
  • 1ESTEC/European Space Agency, Noordwijk, The Netherlands
  • 2Space Science and Applications, Los Alamos National Laboratory, Los Alamos, NM, USA
  • *now at: Centre d'Etude Spatiale des Rayonnements, CNRS, Toulouse, France

Abstract. We report Double Star spacecraft observations of the dusk-flank magnetopause and its boundary layer under predominantly northward interplanetary magnetic field (IMF). Under such conditions the flank low-latitude boundary layers (LLBL) of the magnetosphere are known to broaden. The primary candidate processes associated with the transport of solar wind plasma into the LLBL are: (1) local diffusive plasma transport associated with the Kelvin-Helmholtz instability (KHI), (2) local plasma penetration owing to magnetic reconnection in the vicinity of the KHI-driven vortices, and (3) via a pre-existing boundary layer formed through double high-latitude reconnection on the dayside. Previous studies have shown that a cold population of solar wind origin is typically mixed with a hot population of magnetospheric origin in the LLBL. The present observations show the coexistence of three distinct ion populations in the dusk LLBL, during an interval when the magnetopause is unstable to the KHI: (1) a typical hot magnetospheric population, (2) a cold population that shows parallel temperature anisotropy, and (3) a distinct third cold population that shows perpendicular temperature anisotropy. Although no unambiguous conclusion may be drawn from this single event, we discuss the possible mechanisms at work and the origin of each population by envisaging three likely sources: hot magnetospheric plasma sheet, cold magnetosheath of solar wind origin, and cold plasma of ionospheric origin.

Publications Copernicus
Download
Citation