On electromagnetic forces and works done by them

摘要

In this work, a problem of description of interaction of electromagnetic field with matter is studied. This problem is directly related to another problem of construction of energy-momentum tensor of electromagnetic field in a space filled with bodies of different matter. For both problems, an important role is played by a choice of method of electromagnetic field description, that is, a choice of field vectors amongst admissible pairs E and H, D and B, D and H, E and B. In the present paper, we show that a sum of electromagnetic forces applied to a body with matter and speed of changing electromagnetic momentum in a domain occupied by this body, and also a sum of works, performed by electromagnetic forces per unit time and speed of changing of electromagnetic energy in the same domain, filled with the body, take the values that do not depend on admissible pair of field vector used for description of process of interaction between matter and electromagnetic field. This leads to an opportunity to make use of sums mentioned above as main suitable characteristics of interaction between matter and electromagnetic field.