Waves in a Hot Plasma — 1. General Features

Abstract

In the previous chapter we have treated a plasma as a mixture of ion and electron fluids each characterized by an isotropic pressure. Each element of the fluid moves locally under the influence of the local field of the wave. In so doing we have ignored an important effect. If a particle of the fluid has a speed comparable with the wave speed then during one period of the oscillation the particle moves distances comparable with the wavelength and therefore experiences completely different forces from those experienced by a particle with a different energy. These particles may remain in phase with the wave over many wave periods and this leads to resonant effects. Energy may be transferred efficiently between waves and particles. This chapter deals with the linear theory of some such waves. New effects appear among which are the phenomenon of Landau damping, various wave growth effects and a modes which do not correspond to any so far found. These can be treated by solving the Vlasov equation self-consistently with Maxwell’s equations.