Articles | Volume 30, issue 1
Ann. Geophys., 30, 33–48, 2012
Ann. Geophys., 30, 33–48, 2012

Regular paper 05 Jan 2012

Regular paper | 05 Jan 2012

Supermagnetosonic subsolar magnetosheath jets and their effects: from the solar wind to the ionospheric convection

H. Hietala1, N. Partamies2, T. V. Laitinen2, L. B. N. Clausen3, G. Facskó4,2, A. Vaivads5, H. E. J. Koskinen2,1, I. Dandouras6,7, H. Rème6,7, and E. A. Lucek8 H. Hietala et al.
  • 1Department of Physics, University of Helsinki, P.O. Box 64, 00014 Helsinki, Finland
  • 2Finnish Meteorological Institute, P.O. Box 503, 00101 Helsinki, Finland
  • 3Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, VA 24061-0002, USA
  • 4Geodetic and Geophysical Research Institute, Hungarian Academy of Sciences, 9401 Sopron, Pf. 5, Hungary
  • 5Swedish Institute of Space Physics, P.O. Box 537, 75121 Uppsala, Sweden
  • 6Inst. de Recherche en Astrophysique et Planétologie (IRAP), Univ. of Toulouse, UPS, B.P. 44346, 31028 Toulouse, France
  • 7IRAP/CNRS, UMR5187, B.P. 44346, 31028 Toulouse, France
  • 8The Blackett Laboratory, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK

Abstract. It has recently been proposed that ripples inherent to the bow shock during radial interplanetary magnetic field (IMF) may produce local high speed flows in the magnetosheath. These jets can have a dynamic pressure much larger than the dynamic pressure of the solar wind. On 17 March 2007, several jets of this type were observed by the Cluster spacecraft. We study in detail these jets and their effects on the magnetopause, the magnetosphere, and the ionospheric convection. We find that (1) the jets could have a scale size of up to a few RE but less than ~6 RE transverse to the XGSE axis; (2) the jets caused significant local magnetopause perturbations due to their high dynamic pressure; (3) during the period when the jets were observed, irregular pulsations at the geostationary orbit and localised flow enhancements in the ionosphere were detected. We suggest that these inner magnetospheric phenomena were caused by the magnetosheath jets.