Reconstruction of a large-scale reconnection exhaust structure in the solar wind

Teh Wai Leong, B. U Ö Sonnerup, Q. Hu, C. J. Farrugia

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

We recover two-dimensional (2-D) magnetic field and flow field configurations from three spacecraft encounters with a single large-scale reconnection exhaust structure in the solar wind, using a new reconstruction method (Sonnerup and Teh, 2008) based on the ideal single-fluid MHD equations in a steady-state, 2-D geometry. The reconstruction is performed in the rest frame of the X-line, where the flow into, and the plasma jetting within, the exhaust region are clearly visible. The event was first identified by Phan et al. (2006) in the ACE, Cluster, and Wind data sets; they argued that quasi-steady reconnection persisted for over 2 h at a long (390RE) X-line. The reconnection exhaust is sandwiched between two discontinuities, both of which contain elements of intermediate- and slow-mode behavior; these elements are co-located rather than being spatially separated. These composite discontinuities do not satisfy the coplanarity condition or the standard MHD jump conditions. For all three spacecraft, theWalén regression line slope was positive (negative) for the leading (trailing) discontinuity. Our MHD reconstruction shows that: (1) the X-line orientation was close to the bisector of the overall magnetic shear angle and exhibited a slow rotating motion toward the Sun-Earth line; (2) the X-line moved earthward, dawnward, and southward; (3) the reconnection electric field was small (̃0.02 mV/m on average) and gradually decreased from the first crossing (ACE) to the last (Wind). The magnetic field and flow field configurations recovered from ACE and Cluster are similar while those recovered from Wind also include a magnetic island and an associated vortex. Reconnection persisted for at least 2.4 h involving inflow into the exhaust region from its two sides. Time-dependence in the reconnection electric fields seen by ACE and Wind indicates local temporal variations in the field configuration. In addition to the reconstruction results, we provide a description and analysis of many details from the crossings by the spacecraft.

Original languageEnglish
Pages (from-to)807-822
Number of pages16
JournalAnnales Geophysicae
Volume27
Issue number2
DOIs
Publication statusPublished - 9 Feb 2009
Externally publishedYes

Fingerprint

solar wind
discontinuity
spacecraft
flow field
electric field
flow distribution
configurations
coplanarity
magnetic field
magnetic islands
electric fields
magnetic fields
encounters
time dependence
vortex
regression analysis
sun
inflow
temporal variation
vortices

Keywords

  • Discontinuities
  • Kinetic and MHD theory
  • Magnetic reconnection
  • Space plasma physics

ASJC Scopus subject areas

  • Earth and Planetary Sciences (miscellaneous)
  • Atmospheric Science
  • Astronomy and Astrophysics
  • Space and Planetary Science
  • Geology

Cite this

Reconstruction of a large-scale reconnection exhaust structure in the solar wind. / Wai Leong, Teh; Sonnerup, B. U Ö; Hu, Q.; Farrugia, C. J.

In: Annales Geophysicae, Vol. 27, No. 2, 09.02.2009, p. 807-822.

Research output: Contribution to journalArticle

Wai Leong, Teh ; Sonnerup, B. U Ö ; Hu, Q. ; Farrugia, C. J. / Reconstruction of a large-scale reconnection exhaust structure in the solar wind. In: Annales Geophysicae. 2009 ; Vol. 27, No. 2. pp. 807-822.
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