Magnetostriction Electromagnetic–Acoustic Conversion in a Normal Polarizing Field

The calculation of the direct electromagnetic acoustic conversion (EMAC) for a loop with current, independent of the generation mechanism—that is, in the general form—is presented. The direct EMAC from a circular planar coil with current in a normal polarizing field is considered as an example. Other problems involving specific generation mechanisms (in particular, the Lorentz magnetic force, which is not taken into account in this work, and a tangential polarizing field in the case of a loop with current), can be considered as particular cases. Calculations of the projections of displacements of the acoustic field generated by the magnetostriction mechanism have been carried out for a polarizing magnetic field that is normal to the interface using the model of a two-conductor plane with current. It has been found that the spectral densities of the elastic displacements, e.g., those excited by the magnetostriction mechanism, obey the same regularities (are similar to each other), irrespective of the direction of the polarizing field and the geometry of the source.