Generalized Onsager fluxes based on inexact differential 1-form

Abstract

Abstract Onsager fluxes proposed by D.G.B. Edelen assume that the same symmetry, nonlinear Onsager reciprocal relations, holds near and far from equilibrium. This assumption leads to exact differential 1-form J ⋅ dX everywhere, where J and X are thermodynamic fluxes and forces, respectively. However, thermodynamic fluxes far from equilibrium are characterized by symmetry breaking, which lead to the inexact differential 1-form. It is shown in this paper that the inexact differential 1-form J ⋅ dX should be represented by multiple independent scalar-valued functions. Generalized Onsager fluxes are obtained based on such representation. Generalized Onsager fluxes do not satisfy the nonlinear Onsager reciprocal relations and contain multiple independent scalar-valued functions, so they are suitable to thermodynamic fluxes far from equilibrium. Generalized Onsager fluxes embody Onsager fluxes as a special case. Therefore, generalized Onsager fluxes provide a unified framework for thermodynamic fluxes near and far from equilibrium.