Articles | Volume 23, issue 8
08 Nov 2005
 | 08 Nov 2005

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

Z. Y. Pu, C. J. Xiao, X. G. Zhang, Z. Y. Huang, S. Y. Fu, Z. X. Liu, M. W. Dunlop, Q. G. Zong, C. M. Carr, H. Réme, I. Dandouras, A. Fazakerley, T. Phan, T. L. Zhang, H. Zhang, and X. G. Wang

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.