Open AccessReflection of SH in the Presence of a Magnetic Field
Author(s) -
Gans Roger F.
Publication year - 1972
Publication title -
geophysical journal of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0016-8009
DOI - 10.1111/j.1365-246x.1972.tb02206.x
Subject(s) - earth's magnetic field , magnetic field , geophysics , reflection (computer programming) , mantle (geology) , viscosity , physics , condensed matter physics , geology , thermodynamics , quantum mechanics , computer science , programming language
Summary The hypothesis that the geomagnetic field at the core‐mantle boundary can induce an effective viscosity sufficient to give SH reflection coefficients significantly different from unity is investigated in detail for incident SH waves with the magnetic field in the plane of incidence. For earthlike parameters the effective viscosity is found to besmaller than any theoretical estimates. Here μ is viscosity, β cos θ the normal component of the magnetic field, p density, σ electrical conductivity and ω the frequency of the incident wave. Primed quantities are measured in the mantle and unprimed in the core. It is suggested that a (comparatively) thin zone of high effective viscosity, 5–10 km thick, could resolve the discrepancy between theoretical and seismic core viscosity estimates.