The papers presented in this volume are taken from the Proceedings of Symposium 6 and Topical Meetings D2 and D4 of the COSPAR Twenty-eighth Plenary meeting held in The Hague. The papers have been divided into three chapters, Role of Plasma Waves in the Physics of Planetary Environments, Particle Populations in Magnetospheric Current Sheets and Quasi-Parallel and Parallel Shocks.