Yasuhito Narita Knihy

Dynamics of astrophysical systems is often described by plasma physics, yet understanding the nature of plasma turbulence remains as a challenge in physics in both theories and experiments. This book is an up-to-date summary and review of recent results in research on waves and turbulence in near-Earth space plasma turbulence, obtained by Cluster , the multi-spacecraft mission. Spatial and temporal structures of solar wind turbulence as well as its interaction with the bow shock ahead of the Earth are presented using Cluster data. The book presents (1) historical developments, (2) theoretical background of plasma physics, turbulence theories, and the plasma physical picture of the solar system, (3) analysis methods for multi-spacecraft data, (4) results of Cluster data analysis, and (5) impacts on astrophysics and Earth sciences.

Near-Earth space such as the solar wind and the terrestrial magnetosphere serves as a natural laboratory for studying fundamental properties of plasma turbulence, and has important implications to astrophysical applications. While earlier spacecraft observations revealed that magnetic field fluctuations are reminiscent of turbulence in these regions, the observations were primarily limited to single-spacecraft measurements and separation between spatial structures and temporal variations has always been a matter of debate in interpreting the data. With the advent of the Cluster mission, the four-spacecraft mission, it has become possible to determine the three-dimensional spatial structures of plasma turbulence directly in near-Earth space. Analysis methods of plasma turbulence are developed for multi-spacecraft measurements and applied to the Cluster data for the first time. The multi-point analysis methods enable us to investigate fluctuation properties not only in frequency but also in wave vector domain, visualizing symmetric properties of turbulence and thus opening a new gate for studying turbulence. Fundamental questions are spotlighted on the nonlinear nature of turbulence, which are challenges in both theoretical and experimental physics.