Grad-Shafranov reconstruction with field-aligned flow

First results

Teh Wai Leong, B. U Ö Sonnerup, L. N. Hau

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

Grad-Shafranov (GS) reconstruction is a novel tool for recovering steady two-dimensional (2-D) coherent magnetic field structures from data taken by a single spacecraft. We present first results from a recently developed version of GS reconstruction that incorporates the effects of dynamically significant field-aligned plasma flow. A new GS solver for this case has been developed and is benchmarked with an exact analytical solution. It is then applied to a magnetopause encounter by Cluster 1 (C1) and Cluster 3 (C3) on July 5, 2001. In the C1 crossing, a field-aligned plasma flow, in the frame co-moving with the local magnetopause structures, is present at approximately 57% of the Alfvén speed; in the C3 event the local flow is nearly Alfvénic. We find the following: (1) The recovered field maps are qualitatively similar to those obtained from magneto-hydrostatic GS reconstruction, indicating that the latter can be fairly robust. (2) Our code provides new information about plasma structure and supersonic field-aligned flow effects during reconnection. (3) We confirm results from the previous GS studies of the event, which indicated that significant time evolution occurred in the 30 s time lapse between the two crossings, owing to developing reconnection at a site close to the spacecraft. We provide an estimate of 0.47 mV/m for the reconnection electric field.

Original languageEnglish
Article numberL05109
JournalGeophysical Research Letters
Volume34
Issue number5
DOIs
Publication statusPublished - 16 Mar 2007
Externally publishedYes

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flow field
magnetopause
plasma
spacecraft
magnetohydrodynamic flow
hydrostatics
electric field
encounters
magnetic field
electric fields
estimates
magnetic fields
effect
code
speed

ASJC Scopus subject areas

  • Earth and Planetary Sciences (miscellaneous)

Cite this

Grad-Shafranov reconstruction with field-aligned flow : First results. / Wai Leong, Teh; Sonnerup, B. U Ö; Hau, L. N.

In: Geophysical Research Letters, Vol. 34, No. 5, L05109, 16.03.2007.

Research output: Contribution to journalArticle

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