ABSTRACT
In many ways, electromagnetic acoustic transducers (EMATs) are very simple devices; a pulse of current through one or several wires (a coil) placed in a magnetic field generates a pulse of ultrasonic energy in a metal. The underlying physics of this coupling (going from energy in an electromagnetic field to energy in an elastic wave) is very well understood. In addition to first principles derivations of practical quantities such as insertion loss or
transfer impedance (these are defined later), there are simpler models that yield the same results. The first principles derivations are useful as they show exactly where the various models break down.
