Magneto-elastic wave propagation

Summary

The effect of a uniform, externally applied magnetic field on the directional distribution and attenuation of waves created by a localised periodic body force in a homogeneous, isotropic elastic solid has been studied using a technique developed by Lighthill. In the absence of the magnetic field irrotational waves and the equivoluminal waves propagate in all directions with velocityv _p andv _s respectively and they decay liker ⁻¹ in all directions. In the presence of the magnetic field, the waves still propagate in all directions but the velocity of irrotational waves increases fromv _s along the magnetic lines of force to (v ² _p +a ²₁ )^1/2 at right angles to them and they decay liker ⁻¹ in all directions. The velocity of equivoluminal waves increases fromv _s at right angles to the magnetic lines of force to (v ² _s +a ²₁ )^1/2 along them and in certain directions they decay liker ^−5/6 while in all other directions they decay liker ⁻¹.