The Plasma State: Definition and Orders of Magnitude of Principal Quantities

Abstract

This is the introductory part of the text-book. Plasma is a medium composed of electrons and ions, free to move in all spatial directions. Because a charged particle can interact simultaneously with many other charged particles in its vicinity (defined by the Debye length), plasma behaves as a collective medium and is macroscopically electrically neutral. The chapter aims at presenting the basic parameters required to acquire an initial knowledge of the plasma state, such as the Debye length, the electron plasma frequency, the various types of collision between particles and their description through specific cross-sections. One can consider the notions presented in this chapter as being developed iteratively since these quantities are considered in more detail and quantitatively in the subsequent chapters.