Abstract: A method for characterizing electromagnetic interaction systems using thermodynamic methods is proposed. Thermodynamic systems can be equivalently transformed by Jacobian determinant for partial derivatives characterizing mechanical and thermal effects. A system can be divided into multiple corresponding subsystems according to its mechanic, thermal, electric and magnetic properties. The associated equivalent effects of the related effects can be derived concisely and quickly by Jacobian determinants, such as the equivalent relationship between obtaining magnetism directly by applying an electric field and obtaining electricity by applying a magnetic field, or the complex effects can be decomposed into multiple simple effects through the electricity-mechanics and mechanics-magnetism relationships, and the correlations can be established by using the Jacobian determinants. The analysis methods of electricity and magnetism are provided through equivalent transformation.

Key words:  thermodynamic effect, electromagnetic coupling, Jacobian determinant, equivalent transformation