Cyclotron radiation from electron streams gyrating in the Jovian magnetosphere, the terrestrial exosphere and the solar active corona.

All identified radio sources, except for line emissions, are regions of plasma, and the study of radio astronomy is, therefore, inherently linked up with the study of behaviour of waves in a plasma. In this chapter, we will thus firstly outline some basic concepts concerning the description of a plasma and its response to electromagnetic disturbances (sections (A) to (G)). An introduction to the problems attacked in this thesis is then given in sections(H) and (I). Gaussian units will be used in this thesis.