Hydrodynamics of magnetic and dielectric fluids in interaction with the electromagnetic field

The hydrodynamics of polar fluids and suspensions in interaction with the e lectromagnetic field is studied in the framework of irreversible thermodyna mics. It is shown that the approach developed earlier by de Groot and Mazur can be extended to include intrinsic rotation and a decomposition of polar ization and magnetization into slow and fast parts. An expression for the e ntropy production is derived which leads to phenomenological relaxation equ ations. For incompressible fluids these reduce to relaxation equations post ulated in the literature. If it is assumed that intrinsic rotation decays m uch faster than the other variables, then a simplified description is possi ble in which the intrinsic angular momentum does not occur. Several propose d expressions for electromagnetic stress tensor and force density are discu ssed and shown to be inadequate. (C) 1999 American Institute of Physics. [S 0021-9606(99)50615-6].