Articles | Volume 23, issue 8
Ann. Geophys., 23, 2889–2895, 2005

Special issue: Double Star - First Results

Ann. Geophys., 23, 2889–2895, 2005

  08 Nov 2005

08 Nov 2005

Double Star TC-1 observations of component reconnection at the dayside magnetopause: a preliminary study

Z. Y. Pu3,1, C. J. Xiao2, X. G. Zhang1, Z. Y. Huang1, S. Y. Fu1, Z. X. Liu3, M. W. Dunlop4, Q. G. Zong5, C. M. Carr6, H. Réme7, I. Dandouras7, A. Fazakerley8, T. Phan9, T. L. Zhang10, H. Zhang1, and X. G. Wang11 Z. Y. Pu et al.
  • 1School of Earth and Space Sciences, Peking University, Beijing 100871, China
  • 2National Astronomical Observatories, Chinese Academy of Science, Beijing 100012, China
  • 3Center for Space Science and Applied Research, Chinese Academy of Science, Beijing 100080, China
  • 4Space Science and Technology Department, Rutherford Appleton Laboratory, Chilton, Oxfordshire, OX11 0QX, UK
  • 5Center for Space Physics, Boston University, Boston, Mass 02215, USA
  • 6SAPG, The Blackett Laboratory, Imperial College, London SW7 2BZ, UK
  • 7Centre d’Etudes Spatiale des Rayonnements, BP 4346, 31028 Toulouse cedex 4, France
  • 8Mullard Space Science Laboratory, University College London, Surrey RH5 6NT, UK
  • 9Space Science Laboratory, University of California Berkeley, Berkeley CA 94720, USA100080, China
  • 10Space Research Institute, Austrian Academy of Sciences, OAW, Graz, A-8010, Austria
  • 11Center for Plasma Physics, Dalian Univerity of Science and Technology, Dalian 116024, China

Abstract. In spring 2004 Double Star TC-1 measured a number of reconnection signatures at the dayside low-latitude magnetopause (MP) when there was a notable By component in the magnetosheath. In a number of events we can show that reconnection was operating nearby TC-1 in the subsolar MP region. In this paper we describe three representative events: (a) event on 21 March 2004 in which the reconnection site can be remotely monitored, the spacecraft was passing by the X-line; (b) event on 12 March 2004 in which TC-1 observed the magnetospheric part of the quadrupolar field, together with a consistent flow reversal; (c) event on 26 March 2004 which occurred for northward IMF, TC-1 observed a reversal of vy across the equatorial MP. In these events the shear angles across the MP were considerably smaller than 180°; a noticeable guide field was present. These observations are consistent with near equatorial component merging, suggesting that component reconnection preferably occurs at the dayside low-latitude MP. There is evidence that when a pronounced magnetic shear across the MP exists in the By component, reconnection may operate at the dayside low-latitude MP for northward IMF Bz.