Comments on "Maximum or minimum entropy production ? How to select a necessary criterion of stability for a dissipative fluid or plasma"

TL;DR

This paper critiques a recent attempt to derive stability criteria for dissipative fluids and plasmas, demonstrating that the proposed equations are thermodynamically inconsistent and that no variational principle exists outside the Onsager region.

Contribution

It clarifies the limitations of thermodynamic stability criteria for dissipative systems, emphasizing the invalidity of previous equations outside the Onsager region.

Findings

The proposed equations are thermodynamically inconsistent.

No variational principle for stability exists outside the Onsager region.

Previous criteria are invalid for systems with convective effects.

Abstract

In a recent paper, Phys. Rev E 81, 041137 (2010), the author attempts to derive ten necessary conditions for stability of dissipative fluids and plasmas. Assuming the validity of the local equilibrium principle, these criteria have been obtained solely from the first and the second laws of thermodynamics. The Onsager reciprocity relations have not been invoked and author's results are supposed to be valid independently of the choice of the boundary conditions. In the present paper, in agreement with the general theory established by Glansdorff-Prigogine in 1954 and 1970, we shall show that there is no variational principle expressing the necessary conditions for stability of dissipative systems involving convective effects when the system is out of the Onsager region. In particular, we shall prove that the basic equations constituting the starting point of the analysis of the author, attempting to derive ten necessary conditions for the stability involving magneto-hydrodynamical effects, are incorrect and in contradiction with the laws of the thermodynamics of irreversible processes.