On the scattering of sound by a magnetic field in a MHD fluid
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We investigate the effect of a localized magnetic field on the propagation of sound in an infinite fluid described by the magnetohydrodynamic equations (MHD). An externally imposed magnetic field will scatter an acoustic wave, and the scattered wave is related to the spatial structure of the magnetic field. Measuring it is thus a non-intrusive probe for the magnetic field. Simple examples likely to be encountered in practice are worked out, and estimates are given that suggest the practical feasability of this diagnostic tool in current MHD experiments.
KeywordsMagnetic Field Diagnostic Tool Spatial Structure Acoustic Wave Scattered Wave
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- 1.For a recent review of these issues, see F. Lund, in Sound-Flow interaction, edited by Y. Aurégan, A. Maurel, V. Pagneux, J.F. Pinton, Lectures Notes in Physics 586 (Springer-Verlag, 2002)Google Scholar
- 2.H.K. Moffatt, Magnetic field generation in electrically conducting fluids (Cambridge University Press, 1978)Google Scholar
- 4.L.M. Lyamshev, A.T. Skvortsov, Sov. Phys. Acoust. 36, 438-439 (1990)Google Scholar
- 5.L. Brekhovskikh, V. Goncharov, Mechanics of Continua and Wave Dynamics (Springer-Verlag, Berlin, 1985), Chap. 13Google Scholar
- 6.This expression can be obtained with standard methods, such as Helmholtz potentials. For a lucid exposition of these methods see K. Aki, P.G. Richards, Quantitative Seismology, Theory and methods (Freeman, 1980), Chap. 4Google Scholar
- 7.S. Nascimbene, Rapport de ma\^ıtrise de l’ENS 2002, in French (unpublished)Google Scholar