Eur. Phys. J. D (2016) 70: 251
https://doi.org/10.1140/epjd/e2016-70474-0

Topical Review

Non-equilibrium in low-temperature plasmas

CNR NANOTEC – PLasMI Lab, via Amendola 122/D, 70126 Bari, Italy

^a e-mail: francesco.taccogna@cnr.it

Received: 26 July 2016
Received in final form: 4 October 2016
Published online: 22 November 2016

Abstract

The wide range of applications of cold plasmas originates from their special characteristic of being a physical system out of thermodynamic equilibrium. This property enhances its reactivity at low gas temperature and allows to obtain macroscopic effects with a moderate energy consumption. In this review, the basic concepts of non-equilibrium in ionized gases are treated by showing why and how non-equilibrium functions of the degrees of freedom are formed in a variety of natural and man-made plasmas with particular emphasis on the progress made in the last decade. The modern point of view of a molecular basis of non-equilibrium and of a state-to-state kinetic approach is adopted. Computational and diagnostic techniques used to investigate the non-equilibrium conditions are also surveyed.