Download or read book Coronal Expansion and Solar Wind written by A. J. Hundhausen and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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. The present volume is an attempt to synthesize the solar wind observations and coronal expansion models from this decade of rapid development. The ultimate goal is, of course, the interpretation of observed solar wind phenomena as the effects of basic physical processes occurring in the coronal and interplanetary plasma and as the natural manifestations of solar properties and structures. This approach implies an emphasis upon the "large-scale" features revealed by the observations. It requires extensive use of the concepts and methods of fluid mechanics.
Download or read book Coronal Holes and Solar Wind Acceleration written by John L. Kohl and published by Springer Science & Business Media. This book was released on 2013-11-09 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: The SOHO-7 Workshop was held from 28 September through 1 October 1998 at the Asticou Inn in Northeast Harbor, Maine. The primary topic of this Workshop was the impact of SOHO observations on our understanding of the nature and evolution of coronal holes and the acceleration and composition of the solar wind. The presentations and discussions occasionally went beyond this topic to include the impact of the reported research on other solar structures and the heliosphere. SOHO (the Solar and Heliospheric Observatory), a project of international cooperation between ESA and NASA, was launched in December 1995 and began its science operations during the first few months of 1996. To many solar and space physicists, it was a great advantage that SOHO began itscomprehensive look at the Sun during the 1996 solar minimum. The qualitatively simple two-phase corona, with polar coronal holes expanding into the high-speed solar wind, and a steady equatorial streamer belt related somehow to the stochastic slow-speed solar wind, allowed various SOHO diagnostics to be initiated with a reasonably well understoodcircumsolar geometry. The analysis of subsequentSOHO measurements made during the rising phase of solar cycle 23 will continue to benefit from what has been learned from the first two years of data.
Download or read book Physics of the Solar Corona written by Constantin J. Macris and published by . This book was released on 1971 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mapping the Solar Wind from Its Source Region Into the Outer Corona written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-16 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: The solar wind not only forms the space environment of Earth and other planets, but is also the cause of many phenomena observed in the Earth's atmosphere, such as aurorae. The expansion of the coronal plasma of the Sun is characteristic to many main sequence stars, and thus provides an example for understanding stellar winds as well. In spite of its importance for both space science and stellar physics, basic solar wind properties remain essentially unresolved. Since its discovery about 50 years ago, the complexity of the Sun corona - solar wind system has complicated the interpretation of observations. Recent progress in remote sensing observations as provided for example by YOHKOH, SOHO, SPARTAN and ULYSSES as well as some ground based techniques such as Interplanetary Scintillation observations, offer a compelling opportunity to unravel the 50 year old puzzle regarding the heat source or sources that cause the expansion of the solar corona. The new era of solar wind observations initiated by SOHO and ULYSSES, have also led to a wealth of new theoretical approaches. The goal of the proposed research was to carry out an integrated study of the coronal and solar wind plasma making use of the opportunities provided by the above spacecraft, as well as plasma emission calculations and new ideas on solar wind expansion theory. Esser, Ruth and Wagner, William J. (Technical Monitor) Goddard Space Flight Center
Download or read book The Solar Wind written by J. R. Herring and published by . This book was released on 1960 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Parker's model of a spherically expanding corona, the "solar wind," is compared with D.E. Blackwell's observations of the 1954 minimum equatorial corona. A significant discrepancy is found between the predicted and the observed electron densities at distances from the sun greater than 20 solar radii. Blackwell's data are found to be consistent with a model in which the corona expands mostly within a disk less than 25 solar radii thick, lying within the sun's equatorial plane. The thickness of the disk as a function of distance from the sun is qualitatively explained in terms of magnetic pressure. The solar wind is found to have a considerable effect on the lunar atmosphere. First, the calculated density of the lunar atmosphere is greatly reduced by collisions with protons in the solar wind. If the flux of particles in this wind has the conventional values ranging between 10(exp 10) to 10(exp 11) per sq cm-sec, the calculations yield a lunar pressure of 10(exp -13) atmosphere of argon, in agreement with the value predicted by Elsmore and Whitfield on the basis of observations on the occultation of radio stars. Second, following a suggestion by Gold, it was found that the collisions of solar-wind protons with the lunar surface produce an atmosphere of cold neutral hydrogen with a density of 10(exp 5) per cu cm at the lunar surface. The density falls off at greater distances in accordance with the inverse-square law. Estimates indicate that the interaction of solar particles with the neutral hydrogen will produce an extended lunar ionosphere with a density of the order of 400 protons/cu cm in the vicinity of the moon."
Download or read book A View of Solar Magnetic Fields the Solar Corona and the Solar Wind in Three Dimensions written by John M. Wilcox and published by . This book was released on 1978 with total page 29 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the last few years it was learned that the solar corona and the solar wind are three-dimensional. That is, the deviations from spherical or even cylindrical symmetry and first-order effects, that are important for our basic description and indeed physical understanding of the coronal expansion. The recognition of this simple fact has been a slow process; perhaps because it complicates the mathematical treatment. Even a quick look at the solar corona reveals a highly structured medium with large density gradients. It has long- almost for a century as a matter of fact (Bigelow, 1889)- been suggested that magnetic fields are the fundamental agent that controls the shape of the corona and determines the inner boundary conditions for the solar wind escape. Only recently have we recognized how dominant is the role of large-scale magnetic fields in determining the global structure of the solar wind. The highly successful 'SKYLAB Workshop on Coronal Holes' that was conducted last year has been important for the general acceptance of the new three-dimensional description of the structure of the corona and the interplanetary magnetic field. Zirker (1977) and Hundhausen (1977) have aptly summarized the insight resulting from this work. The present review will attempt a further synthesis based on a broader database than that available to the Workshop. We will attempt to provide a unified viewpoint recognizing that such an attempt is usually associated with a certain degree of oversimplification.
Download or read book The Solar Corona written by Leon Golub and published by Cambridge University Press. This book was released on 2010 with total page 405 pages. Available in PDF, EPUB and Kindle. Book excerpt: Second edition graduate level textbook giving an up-to-date treatment of our understanding of the solar corona.
Download or read book Coronal Holes and High Speed Wind Streams written by Jack B. Zirker and published by . This book was released on 1977 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Corotating Interaction Regions written by A. Balogh and published by Springer Science & Business Media. This book was released on 2000-01-31 with total page 508 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume gives a comprehensive and integrated overview of current knowledge and understanding of corotating interaction regions (CIRs) in the solar wind. It is the result of a workshop at ISSI, where space scientists involved in the Ulysses, Pioneer, Voyager, IMP-8, Wind, and SOHO missions exchanged their data and interpretations with theorists in the fields of solar and heliospheric physics. The book provides a broad synthesis of current understanding of CIRs, which form at the interface between the fast solar wind originating in the northern and southern coronal holes and the slow solar wind that originates near and within coronal streamers surrounding the heliomagnetic equator. CIRs are the dominant structure in the heliosphere near and beyond Earth on the declining phase and near the minimum of the 11-year solar activity cycle. Particles energized at the shocks that bound CIRs at heliospheric distances beyond the orbit of Earth are the dominant energetic particle population observed in the outer heliosphere at these times. Papers included in this volume cover the subject of CIRs from their dissipation in the outer hemisphere, and include discussions of complexities associated with their evolution with distance from the Sun, their three-dimensional structure, and the myriad effects that CIRs have on energetic particles throughout the heliosphere. The book is intended to provide scientists active in space physics research with an up-to-date status report on current understanding of CIRs and their effects in the heliosphere, and also to serve the advanced graduate student with introductory material on this active field of research.
Download or read book Cosmic Winds and the Heliosphere written by Jack Randolph Jokipii and published by University of Arizona Press. This book was released on 1997-10 with total page 1060 pages. Available in PDF, EPUB and Kindle. Book excerpt: Contributors examine the physics of wind origin and physical phenomena in winds, including heliospheric shocks, magnetohydrodynamic turbulence, and kinetic phenomena--and their interactions with surrounding media. Contributions range from studies of the interstellar cloud surrounding the solar system to solar wind interaction with comets.
Download or read book Introduction to Stellar Winds written by Henny J. G. L. M. Lamers and published by Cambridge University Press. This book was released on 1999-06-17 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first comprehensive introduction to the observations and theories of stellar winds; a long-awaited graduate textbook, written by two founders of the field.
Download or read book Physics of the Inner Heliosphere II written by Rainer Schwenn and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: Physics of the Inner Heliosphere gives for the first time a comprehensive and complete summary of our knowledge of the inner solar system. Using data collected over more than 11 years by the HELIOS twin solar probes, one of the most successful ventures in unmanned space exploration, the authors have compiled six extensive reviews of the physical processes of the inner heliosphere and their relation to the solar atmosphere. Researchers and advanced students in space and plasma physics, astronomy, and solar physics will be surprised to see just how closely the heliosphere is tied to, and how sensitively it depends on, the sun. Volume 2 deals with particles, waves, and turbulence, with chapters on: - magnetic clouds - interplanetary clouds - the solar wind plasma and MHD turbulence - waves and instabilities - energetic particles in the inner solar system
Download or read book SOLAR WINDS written by and published by . This book was released on 1959 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: It is suggested that corpuscular radiation is hydrodynamic expansion of the solar corona which is called solar wind. Arguments are presented for this expansion of the solar corona in terms of motion of the comet tail aurorae production, magnetic storms, and cosmic-ray effects on earth. The corona is taken to be isotherrnal out to an undefined distance (in multiples of the radius of the base of the corona) and from there it expands adiabatically until supersonic velocities are reached at infinity. The solar wind is considered to continue after five astronomical units on the spiralling solar magnetic field. Applications of the solar wind hypothesis to solar sailing are discussed. (C.J.G.).
Download or read book Physics of the Solar Corona written by Markus Aschwanden and published by Springer Science & Business Media. This book was released on 2004-09 with total page 888 pages. Available in PDF, EPUB and Kindle. Book excerpt: A thorough introduction to solar physics based on recent spacecraft observations. The author introduces the solar corona and sets it in the context of basic plasma physics before moving on to discuss plasma instabilities and plasma heating processes. The latest results on coronal heating and radiation are presented. Spectacular phenomena such as solar flares and coronal mass ejections are described in detail, together with their potential effects on the Earth.
Download or read book Solar Wind Acceleration in Coronal Holes High Speed Solar Wind Streams written by and published by . This book was released on 1978 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Past attempts to explain the large solar wind velocities in high speed streams by theoretical models of the expansion have invoked either extended nonthermal heating of the corona, heat flux inhibition, or direct addition of momentum to the expanding coronal plasma. Several workers have shown that inhibiting the heat flux at low coronal densities is probably not adequate to explain quantitatively the observed plasma velocities in high speed streams. It stressed that, in order to account for both these large plasma velocities and the low densities found in coronal holes (from which most high speed streams are believed to emanate), extended heating by itself will not suffice. One needs a nonthermal mechanism to provide the bulk acceleration of the high wind plasma close to the sun, and the most likely candidate at present is direct addition of the momentum carried by outward-propagating waves to the expanding corona. Some form of momentum addition appears to be absolutely necessary if one hopes to build quantitatively self-consistent models of coronal holes and high speed solar wind streams.
Download or read book Solar Polarization written by K.N. Nagendra and published by Springer Science & Business Media. This book was released on 1999-07-31 with total page 558 pages. Available in PDF, EPUB and Kindle. Book excerpt: Novel instruments for high-precision imaging polarimetry have opened new possibilities, including for exploring effects in radiative scattering, atomic physics, spectral line formation, and radiative transfer. This volume gives a comprehensive and up-to-date account of this rapidly evolving and interdisciplinary field of science.
Download or read book Solar Dynamics and its Effects on the Heliosphere and Earth written by Daniel Baker and published by Springer Science & Business Media. This book was released on 2007-11-24 with total page 373 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume helps the reader to understand the ways and means of how dynamical phenomena are generated at the Sun, how they travel through the Heliosphere, and how they affect Earth. It provides an integrated account of the three principal chains of events all the way from the Sun to Earth: the normal solar wind, coronal mass ejections, and solar energetic particles.
