Description
Space plasma phenomena have attracted particular interest since the beginning of the exploration of space about half a century ago. Already a first set of pioneering observations (e.g., Ness, 1969) discovered that matter and electromagnetic fields in space have a complex structure, which was largely unpredicted. Terrestrial and, particularly, spacecraft observations of solar plasmas and fields point in the same direction. In fact, our present picture of the plasma and the electromagnetic fields in space throughout the solar system (and beyond) is that of an extremely complex medium with spatial and temporal variations on large ranges of scales. The wealth of dynamical phenomena observed in space plasmas has steadily increased as more and more refined observational techniques have become available, and it can be expected that important processes still await their detection.
An outstanding class of space plasma phenomena is addressed here under the notion of space plasma activity. Quite generally, in the area of space and astrophysical plasmas the term activity is used for a set of particular magnetospheric, stellar or galactic phenomena, which, although vastly different regarding their space and time scales and their dominant physical processes, have an important characteristic property in common. In all cases they show sudden transitions from relatively quiet states with less pronounced timedependence to dynamic states in a strongly time-dependent evolution. (Note that this property by no means is restricted to plasma phenomena, volcanic activity being a prominent example from another discipline.)
The term activity is commonly used in two different ways. In a narrow sense activity refers to the strongly time-dependent dynamic phase alone. In a wider sense, it means the entire phenomenon including the relevant quiescent intervals. The latter meaning is adopted for the title of this book and, to a large extent, also for the text. It will be clear from the context, when, occasionally, we will use the narrower meaning
Contents
1 Introduction
Part I Setting the scene
2 Sites of activity
3 Plasma models
Part II Quiescence
4 Introduction
5 Magnetohydrostatic states
6 Particle picture of steady states
7 A unified theory of steady states
8 Quasi-static evolution and the formation of thin current sheets
Part III Dynamics
9 Nonideal effects
10 Selected macroinstabilities
11 Magnetic reconnection
12 Aspects of bifurcation and nonlinear dynamics
Part IV Applications
13 Magnetospheric activity
14 Models of solar activity
15 Discussion