Nonequilibrium Processes in the Planetary and Cometary Atmospheres: Theory and Applications


Book Description

This book reviews the approach to the kinetic simulation of nonequilib rium processes in the planetary atmospheres which the authors developed and dealt with since the 1970s. The results of this study, which are focused on the nonequilibrium collisional processes in the atmospheres of planets and comets, are thoroughly reviewed and discussed. Many specific problems of atmospheric modeling, involving numerical evaluation of aeronomic pro cesses, are addressed and compared with the available experimental data. The kinetic approach proved to be especially effective to model the in teraction of the incident shortwave solar radiation with the rarefied gas of planetary upper atmospheres. It involves various processes of photolysis, en ergetic electron impacts, and accompanying numerous chemical reactions, as well as processes occurring in the intermediate ("transition") zones of planetary and cometary gas envelopes. The underlying mathematical treat ment is based on the stochastic approach for the solution of the Boltzmann type equation and implies the development of the efficient algorithms for its computer simulation. Some results of this study were previously summa rized in the monograph issued in Russian (Marov et al. , 1990) and later in the review paper published in Space Science Reviews (Marov et al. , 1996). The basic principles of stochastic simulation were first developed in the field of rarefied gas dynamics and were successfully applied to the solution of some engineering problems of aerodynamics and heat transfer.







Nonequilibrium Processes in the Planetary and Cometary Atmospheres: Theory and Applications


Book Description

This book reviews the approach to the kinetic simulation of nonequilib rium processes in the planetary atmospheres which the authors developed and dealt with since the 1970s. The results of this study, which are focused on the nonequilibrium collisional processes in the atmospheres of planets and comets, are thoroughly reviewed and discussed. Many specific problems of atmospheric modeling, involving numerical evaluation of aeronomic pro cesses, are addressed and compared with the available experimental data. The kinetic approach proved to be especially effective to model the in teraction of the incident shortwave solar radiation with the rarefied gas of planetary upper atmospheres. It involves various processes of photolysis, en ergetic electron impacts, and accompanying numerous chemical reactions, as well as processes occurring in the intermediate ("transition") zones of planetary and cometary gas envelopes. The underlying mathematical treat ment is based on the stochastic approach for the solution of the Boltzmann type equation and implies the development of the efficient algorithms for its computer simulation. Some results of this study were previously summa rized in the monograph issued in Russian (Marov et al. , 1990) and later in the review paper published in Space Science Reviews (Marov et al. , 1996). The basic principles of stochastic simulation were first developed in the field of rarefied gas dynamics and were successfully applied to the solution of some engineering problems of aerodynamics and heat transfer.




Mechanics of Turbulence of Multicomponent Gases


Book Description

Space exploration and advanced astronomy have dramatically expanded our knowledge of outer space and made it possible to study the indepth mechanisms underlying various natural phenomena caused by complex interaction of physical-chemical and dynamical processes in the universe. Huge breakthroughs in astrophysics and the planetary s- ences have led to increasingly complicated models of such media as giant molecular clouds giving birth to stars, protoplanetary accretion disks associated with the solar system’s formation, planetary atmospheres and circumplanetary space. The creation of these models was promoted by the development of basic approaches in modern - chanics and physics paralleled by the great advancement in the computer sciences. As a result, numerous multidimensional non-stationary problems involving the analysis of evolutionary processes can be investigated using wide-range numerical experiments. Turbulence belongs to the most widespread and, at the same time, the most complicated natural phenomena, related to the origin and development of organized structures (- dies of different scale) at a definite flow regime of fluids in essentially non-linear - drodynamic systems. This is also one of the most complex and intriguing sections of the mechanics of fluids. The direct numerical modeling of turbulent flows encounters large mathematical difficulties, while the development of a general turbulence theory is hardly possible because of the complexity of interacting coherent structures. Three-dimensional non-steady motions arise in such a system under loss of la- nar flow stability defined by the critical value of the Reynolds number.




Modern Theoretical and Observational Cosmology


Book Description

Proceedings of the second Hellenic Cosmology Meeting, held in the National Observatory of Athens (Penteli, 19-20 April 2001)




The Image Mission


Book Description

IMAGE (Imager for Magnetopause-to-Aurora Global Exploration) is the first NASA MIDEX mission and the first mission dedicated to imaging the Earth's magnetosphere. This volume offers detailed descriptions of the IMAGE instrumentation and of the image inversion techniques used to interpret the data. Also included are chapters on the IMAGE science objectives, the spacecraft design and capabilities, science and mission operations, and the processing and distribution of IMAGE's nonproprietary data products.




Plasma Astrophysics


Book Description

This textbook is intended as an introduction to the physics of solar and stellar coronae, emphasizing kinetic plasma processes. It is addressed to observational astronomers, graduate students, and advanced undergraduates without a ba- ground in plasma physics. Coronal physics is today a vast field with many different aims and goals. So- ing out the really important aspects of an observed phenomenon and using the physics best suited for the case is a formidable problem. There are already several excellent books, oriented toward the interests of astrophysicists, that deal with the magnetohydrodynamics of stellar atmospheres, radiation transport, and radiation theory. In kinetic processes, the different particle velocities play an important role. This is the case when particle collisions can be neglected, for example in very brief phenomena – such as one period of a high-frequency wave – or in effects produced by energetic particles with very long collision times. Some of the most persistent problems of solar physics, like coronal heating, shock waves, flare energy release, and particle acceleration, are likely to be at least partially related to such p- cesses. Study of the Sun is not regarded here as an end in itself, but as the source of information for more general stellar applications. Our understanding of stellar processes relies heavily, in turn, on our understanding of solar processes. Thus an introduction to what is happening in hot, dilute coronae necessarily starts with the plasma physics of our nearest star.




The Sun and Space Weather


Book Description

Since the Sun is the main source of space weather effects, the first part of the book is devoted to a general introduction to the physics of the Sun. A better understanding of the phenomena underlying solar activity is also important for prediction of solar outbursts and thus for establishing alert systems for space missions and telecommunication systems. The book contains the following topics: possible influence of the Sun on the Earth's climate; the effects of radiation on humans in space and the expected radiation dose from various solar events; disturbances of the Earth's ionosphere and the implications of radio communication at different wavelength ranges; possible hazardous asteroids and meteoroids and their detection; and space debris and special shielding of spacecraft. In the cited literature more detailed information about the topics may be found. This book provides an introduction and overview of modern solar-terrestrial physics for students as well as for researchers in the field of astrophysics, solar physics, geophysics, and climate research.




Multielement System Design in Astronomy and Radio Science


Book Description

The multielement systems have been widely used in many fields of astron omy and radio science in the last decades. This is caused by the increasing demands on the resolution and sensitivity of such systems over the wide range of the electromagnetic wavelengths, from gamma up to radio. The ground-based optical and radio interferometers, gamma-ray and X-ray or bital telescopes, antenna arrays of radio telescopes and also some other radio devices belong to scientific instruments using multielement systems. There fore, the current problems of the optimal construction of such systems, or precisely, those of searching for the best arrangement of the elements in them, were formulated. A rather large number of scientific papers, including those of the authors, is devoted to these problems, and we believe that the time has come to integrate the basic results of the papers into the mono graph. The offered book consists of three parts. The first part is concerned with the optimal synthesis of optical and radio interferometers of various types and purposes; the synthesis of non-equidistant antenna arrays is con sidered in the second part; and the methods for the construction of coded masks for X-ray and gamma-ray orbital telescopes are expounded in the third one. Since in the text combinatorial constructions which are little known to astronomers are used, the necessary information is given in the appendices. Various tables containing the parameters of the systems consid ered are also represented.




Merging Processes in Galaxy Clusters


Book Description

Mergers are the mechanisms by which galaxy clusters are assembled through the hierarchical growth of smaller clusters and groups. Major cluster mergers are the most energetic events in the Universe since the Big Bang. Many of the observed properties of clusters depend on the physics of the merging process. These include substructure, shock, intra cluster plasma temperature and entropy structure, mixing of heavy elements within the intra cluster medium, acceleration of high-energy particles, formation of radio halos and the effects on the galaxy radio emission. This book reviews our current understanding of cluster merging from an observational and theoretical perspective, and is appropriate for both graduate students and researchers in the field.