Coronal Holes And Solar Wind Acceleration

Little more than ten years have passed since spaceprobe-borne instruments con­ clusively demonstrated the existence of the solar wind. These observations con­ firmed the basic validity of a theoretical model, first proposed by E. N. Parker, predicting a continuous, rapid expansion of the solar corona. The subsequent decade has seen a tremendous growth in both the breadth and sophistication of solar wind observations; the properties of the interplanetary plasma near the orbit of the earth are now known in great detail. The theory of the coronal ex­ pansion has also been highly refilled both in the sense of including additional physical processes, and of treating more realistic (time-dependent and non spheri­ cally-symmetric) coronal boundary conditions.

Humans have been observing and studying our Sun for centuries, yet much is still unknown about the processes that drive its behavior. Thanks to a new generation of space missions and ground telescopes, we are poised to dramatically increase our understanding of the Sun and its environment.

This volume presents a full description of the magnetosphere and its effect on the solar wind, climatic modes, the Polar Cap index in relation to magnetosphere disturbances (substorms and magnetic storms), recent developments and challenges in developed ionosphere models, and more.

This book addresses and reviews many of the still little understood questions related to the processes underlying planetary magnetic fields and their interaction with the solar wind. With focus on research carried out within the German Priority Program ”PlanetMag”,

This book addresses and reviews many of the still little understood questions related to the processes underlying planetary magnetic fields and their interaction with the solar wind. With focus on research carried out within the German Priority Program ”PlanetMag”, it also provides an overview of the most recent research in the field.

This book presents two important new findings. First, it demonstrates from first principles that turbulent heating offers an explanation for the non-adiabatic decay of proton temperature in solar wind. Until now, this was only proved with reduced or phenomenological models. Second, the book demonstrates that the two types of anisotropy of turbulent fluctuations that are observed in solar wind at 1AU originate not only from two distinct classes of conditions near the Sun but also from the imbalance in Alfvén wave populations. These anisotropies do not affect the overall turbulent heating if we take into account the relation observed in solar wind between anisotropy and Alfvén wave imbalance.