ABSTRACT
This chapter traces the history of plasma research back to the time of Michael Faraday's study of the "dark discharges". It provides the equation of motion describing the temporal behavior of density fluctuations in plasma. The chapter describes that plasma is characterized by a fascinating interplay between its mediumlike character due to the long-range nature of the Coulomb interaction and the individual-particlelike behavior. It investigates the conditions under which the density fluctuations behave collectively in a plasma. The chapter discusses the plasmas found in nature or in the laboratory that are characterized by temperature and density parameters over a wide range of variation. It is therefore convenient to introduce dimensionless coupling constants, called Coulomb coupling parameters, which characterize strengths of the particle interactions in those various charged-particle systems. The chapter also considers the Coulomb cross sections for transfer of momentum and energy.
