General Characterization of a Two-Fluid Anisotropic Warm Plasma in Principal Coordinates

A macroscopic characterization of a two-fluid compressible plasma in an external constant magnetic field is suggested in this paper by the introduction of two "compressivity tensors," one for the electrons and one for the ions, as new constitutive parameters. A new set of four governing equations is formulated which are mathematically concise and are amenable to meaningful physical interpretation. Because the compressivity tensors and the permittivity tensor are Hermitian and pairwise commutative, a unitary transformation is found which simultaneously diagonalizes the matrix forms of all three parameter tensors. This permits a change of basis for the governing equations to a principal coordinate system. The longitudinal components of the electromagnetic fields can then be decoupled from their transverse components.