Principle equivalence and practical difference between two approaches to plasma polarimetry: The Stokes vector formalism and the angular variables technique

In spite of well known different forms of the description of electromagnetic wave polarization state, up to now the evolution of the polarization state in weakly anisotropic media was described only by Stokes vector formalism (SVF) or quasi-istropic approximation (QIA). In this paper different approach is presented, based on angular variables technique (AVT): amplitude ratio and phase shift. It is shown that basic differential equations of angular variables technique can be derived directly from Stokes vector formalism. In turn Segreʹs equations of SVF are derived from the AVT equations, demonstrating the equivalence of the AVT and SVF formalisms. Also some practical distinctions between two approaches are pointed out. It is also shown that AVT explicitibly described interaction between Cotton–Mouton and Faraday effect.