Thermodynamical Discussions for the Basic Equations of Conducting Magnetic Fluids: (Nonrelativistic and Nonpolar Theory)

The governing equations for magnetic fluids with good conductivity of heat and electricity have not been sufficiently discussed thermodynamically. In this paper a new strict simplified method of deriving the basic equations for such conducting magnetic fluids is presented by the thermodynamical method using free energy and dissipation function on the assumptions of the nonrelativistic and nonpolar theory. As results the physically desirable expression of the pressure part and Maxwellian stress in the constitutive equation of stress is derived in a general theory that polarized and magnetized media are exist. Then the following results are obtained from this theory: The surface forces acting on the material control surface include not only stress but also electromagnetic momentum flux density. And pointing vectors in the material volume are observed in the relativistic electromagnetic fields which moves against the fixed system.