Although the plane-wave impedance of vacuum Z0 is a fundamental constant of electromagnetism, it has historically been little used from a strictly theoretical point of view, most often appearing as a derived quantity. Its use is mostly limited to a role as a normalization or reference parameter in electromagnetic engineering applications. However, the recent resolution of the inconsistency in the initial laws of electromagnetism sheds new light on it. This work makes it possible to deepen its interpretation and to show that its actual role is of considerable importance. After clarifying the concept of wave impedance, possible misinterpretations are eliminated, and a study of its physical significance is carried out based on the role (effect or excitation) of electromagnetic fields. It follows that the plane-wave impedance in vacuum is a constant related to the mechanical effects of electromagnetic phenomena. This result, when confronted with the new expressions of the Ampère and Coulomb forces obtained through the resolution of the inconsistency in the original laws of electromagnetism, shows that it is more precisely an electromechanical coupling constant.
Jean-Marc ROUX (Fri,) studied this question.