Local structure of directional discontinuities in the solar wind

Teh Wai Leong, B. U. Sonnerup, G. Paschmann, S. E. Haaland

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

We examine local structures of three directional discontinuities (DDs) observed by Cluster in the solar wind, using reconstruction based on the ideal 2-D MHD equations in a steady state. In this novel application of the technique, our goals are the following: (1) to explain why the minimum variance analysis of the magnetic field (MVAB) often fails to meaningfully predict the vector normal to a DD and (2) to use the reconstructed field maps as an aid in interpreting the differences in the magnetic field profiles recorded by the four Cluster spacecraft. From the maps, we learn that the failure of MVAB as a predictor of the normal direction is due to internal structure such as magnetic islands (flux ropes) within the DDs and also that we can partly understand the differences in the fields observed by the four spacecraft. We find fairly good agreement between the normal directions determined from the four-point timing approach and from MVAB, provided the constraint Bn= 0 is imposed on MVAB. Because of the island structures, the DDs cannot be readily identified as either tangential or rotational discontinuities, although the approximately Alfvénic flows on both sides favor the latter interpretation.

Original languageEnglish
Article numberA04105
JournalJournal of Geophysical Research: Space Physics
Volume116
Issue number4
DOIs
Publication statusPublished - 2011
Externally publishedYes

Fingerprint

Solar wind
magnetic fields
solar wind
Spacecraft
discontinuity
Magnetic fields
ropes
Magnetic flux
Magnetohydrodynamics
Analysis of variance (ANOVA)
analysis of variance
spacecraft
magnetic field
magnetic islands
variance analysis
time measurement
Direction compound
methodology
profiles
predictions

ASJC Scopus subject areas

  • Space and Planetary Science
  • Geophysics

Cite this

Local structure of directional discontinuities in the solar wind. / Wai Leong, Teh; Sonnerup, B. U.; Paschmann, G.; Haaland, S. E.

In: Journal of Geophysical Research: Space Physics, Vol. 116, No. 4, A04105, 2011.

Research output: Contribution to journalArticle

Wai Leong, Teh ; Sonnerup, B. U. ; Paschmann, G. ; Haaland, S. E. / Local structure of directional discontinuities in the solar wind. In: Journal of Geophysical Research: Space Physics. 2011 ; Vol. 116, No. 4.
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