SURFACE-WAVES IN A NONLINEAR MAGNETOELASTIC CONDUCTOR OF FINITE CONDUCTIVITY

We use the basic equations given in a previous paper [1] to investigate the nonlinear surface wave propagation in an isotropic magnetoelastic half-space having finite electric conductivity and subjected to an initial constant magnetic field normal to the sagittal plane. The unknowns of the problem are represented as expansions in a small parameter. The system of equations splits into two problems, one concerning a Rayleigh mode S-R having a ''purely thermoelastic form'' and the other a Bleustein-Gulyaev mode S-BG With an elastic coefficient modified by magnetic effects. The solution in the first and second order approximations for the S-R problem are derived respectively, in terms of one and two unknowns, while the surface wave propagation for the S-BG problem cannot exist. The phase velocity and attenuation constant are obtained and discussed both numerically and graphically for aluminium, copper and lead. The result shows that the phase velocity and the attenuation constant change sharply with the angular frequency omega in the neighbourhood of a characteristic frequency omega* for each medium (similar to the corresponding one in thermoelasticity).