Thermodynamics "beyond" local equilibrium

Nonequilibrium thermodynamics has shown its applicability in a wide variety of different situations pertaining to fields such as physics, chemistry, b iology, and engineering. As successful as it is, however, its current formu lation considers only systems close to equilibrium, those satisfying the so -called local equilibrium hypothesis. Here we show that diffusion processes that occur far away from equilibrium can be viewed as at local equilibrium in a space that includes all the relevant variables in addition to the spa tial coordinate. In this way, nonequilibrium thermodynamics can be used and the difficulties and ambiguities associated with the lack of a thermodynam ic description disappear. We analyze explicitly the inertial effects in dif fusion and outline how the main ideas can be applied to other situations.