Cluster survey of the mid-altitude cusp – Part 2: Large-scale morphology - INSU - Institut national des sciences de l'Univers Access content directly
Journal Articles Annales Geophysicae Year : 2009

Cluster survey of the mid-altitude cusp – Part 2: Large-scale morphology

Abstract

In this second part of our statistical study of the mid-altitude cusp, we compare the cusp morphology, as seen in the Cluster ion spectrometer (CIS), to the interplanetary magnetic field (IMF) orientation. We first recall the method we have used a) to define the cusp properties, b) to sort IMF conditions or behaviour in classes, c) to determine the proper time delay between the solar wind monitors and Cluster. Then, we define a few morphological features of the cusp and we relate these to the prevailing IMF. Our results reveal, among other things, that the occurrence of clearly dispersed ion structures in the cusp is 48%. From these dispersions, we infer the distance to reconnection site, which we relate to external conditions. In all other cases, the cusp exhibits a more disturbed behaviour in terms of ion structures and fall in our "discontinuous" or "irregular" categories. Among these, a few interesting cases of discontinuous cusps occurring under stable IMF conditions have been identified. They all occur when the IMF is dominated by its Y-component, which plays in principle in favour of anti-parallel reconnection but their wide MLT and latitudinal distributions is a priori incompatible with the anti-parallel reconnection hypothesis solely.
Fichier principal
Vignette du fichier
angeo-27-1875-2009.pdf (1.19 Mo) Télécharger le fichier
Origin : Publisher files allowed on an open archive
Loading...

Dates and versions

insu-00363647 , version 1 (27-08-2020)

Licence

Attribution

Identifiers

Cite

Frederic Pitout, C. P. Escoubet, B. Klecker, I. Dandouras. Cluster survey of the mid-altitude cusp – Part 2: Large-scale morphology. Annales Geophysicae, 2009, 27 (5), pp.1875-1886. ⟨10.5194/angeo-27-1875-2009⟩. ⟨insu-00363647⟩
155 View
76 Download

Altmetric

Share

Gmail Facebook X LinkedIn More