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Astron. Astrophys. 347, 1005-1008 (1999)
On the removal of the sign ambiguity in the photospheric transverse magnetic field
T.Z. Boulmezaoud 1,2 and
T. Amari 1,3
1 CNRS URA 2052, Service d'Astrophysique CEA/Saclay, F-91191 Gif sur Yvette Cedex, France
2 Laboratoire d'Analyse Numérique, Université P.&M. Curie, F-75252 Paris Cedex 05, France
3 CNRS, Observatoire de Paris, L.P.S.H., F-92195 Meudon Principal Cedex, France
Received 14 December 1998 / Accepted 25 May 1999
Abstract
We present a method for removing the ambiguity in the transverse component of the photospheric magnetic field measured by vector magnetographs. The method is based upon the use of the divergence-free condition satisfied by the magnetic field in the sense of least squares. The method requires the measurement of the longitudinal component of the magnetic field at two depth levels in the photosphere. The method is is shown to be efficient when compared to other existing methods on some particular analytical force-free magnetic fields.
Key words: Magnetohydrodynamics
(MHD) 
Sun: corona
Sun: magnetic fields
Send offprint requests to: T. Amari (amari@gemini.saclay.cea.fr)
This article contains no SIMBAD objects.
Contents
- 1. Introduction
- 2. The method
- 3. Application to a class of analytical force-free magnetic fields
- 4. Conclusions
- Acknowledgements
- References
© European Southern Observatory (ESO) 1999
Online publication: June 6, 1999
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