An investigation is presented of certain aspects of those gyroresonance interactions which take place between very low frequency VLF electromagnetic waves and charged particle fluxes in the earth's outer ionosphere. These interactions, in which significant amounts of energy can be exchanged between the particle's kinetic energy form and the wave electromagnetic-energy form, are thought to be of importance with respect to the dynamical properties of the earths' outer ionosphere. Specifically two problems are considered. The first problem involves the stability of the outer ionosphere plasma to whistler-mode waves under conditions in which high energy electron fluxes permeate this plasma. The second problem involves the feasibility of the creation or depletion of an artificial radiation belt utilizing the geocyclotron gyroresonance interaction in order to transfer energy between man-made waves and relativistic electrons trapped in the outer ionosphere by the earths' magnetic field near the magnetic equatorial plane.

Comprehensive description of physical, plasma and chemical processes controlling ionospheres for scientists and graduate students.

Nonlinear effects in the ionosphere (cross modulation of radio waves) have been known since the 1930s. Only recently, however, has the rapid increase in the power and directivity of the radio transmitters made it possible to alter the properties of the ionosphere strongly and to modify it artificially by applying radio waves. This has revealed a variety of new physical phenomena. Their study is not only of scien tific interest but also undisputedly of practical interest, and is presently progressing very rapidly. This monograph is devoted to an exposition of the present status of theoretical research on this problem. Particular attention is paid, naturally, to problems in the development of which the author himself took part. It is my pleasant duty to thank V. L. Ginzburg, L. P. Pitaevskii, V. V. Vas'kov, E. E. Tsedilina, A. B. Shvartsburg, and Va. S. Dimant for useful discussions and for valuable remarks during various stages of the work on the problem considered in this book. Contents 1. Introduction . . . . . . . . . . . . . . . . . . .

The distributions of electrons resulting from pitch-angle diffusion due to both wave-particle interactions at high altitudes and binary collisions in the atmosphere have been determined. The results seem to be in agreement with available data, however wave fields which may be too high are required to fit the data. Some of the computational routines and cross sections used in the low-energy (1 eV to 500 eV) portion of the AURORA code have been improved. Processes occurring in the disturbed ionosphere other than collision and magnetic mirroring are inferred by comparing measurements of pitch-angle and energy distributions of electrons in the auroral zones with distributions computed with the AURORA code. (Author).