Evaluation of dynamic characteristics of an electromagnetic ultrasonic transducer

An electromagnetic transducer has been used as a high power stress wave source in nondestructive testings and a detailed analysis of its dynamic characteristics is desired to construct more precise measuring systems. In this paper, first the magnetic field generated by a ring symmetric current on an infinite metal surface with a given waveform is derived. Then, the closed‐form solution of the electromagnetic force per unit volume in metal generated by a zero sectional ring coil is given. As a limiting case, when the conductivity of the metal is infinite, the electromagnetic force can be expressed as the product of time and radial coordinate functions. The characteristics of electromagnetic force per unit volume in metal generated by the zero sectional ring coil are evaluated as the function of conductivity of the metal and the distance between the coil and the surface of metal. It is also shown that Eisenmenger’s [Acustica 12, 185–202 (1962)] treatment is a special case of this formulation when the distan...