ABSTRACT
This chapter discusses the plasma waves in the frequency range extending from a few hertz to a few megahertz and which have their sources within the magnetosphere. It includes the results from very low frequency wave injection experiments at Siple Station, Antarctica, in which the Siple transmitter signals are found to trigger emissions within the magnetosphere. The chapter provides a theoretical background on the propagation and generation mechanisms of plasma waves. It presents the ground and spacecraft observations of plasma waves. It shows that a great advance has been made in the last 35 years since the launch of the first scientific satellite in measuring the characteristics of a large variety of plasma waves in all parts of the magnetosphere. Magnetospheric plasma consisting of electrons and ions of finite temperature and permeated by a magnetic field can support a large variety of electromagnetic, electrostatic, and magnetosonic wave modes that cannot exist in free space.
