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Author: Vo Hong Minh Phan Publisher: ISBN: Category : Languages : en Pages : 0
Book Description
It has been revealed by observational evidences from various experiments at the beginning of the 20th century that the Earth is constantly bombarded by cosmic rays, high-energy particles of extraterrestrial origin. Since these particles are very energetic, it is believed that they could penetrate deep into molecular clouds and ionize the densest parts of these objects where new stars are born. This means that cosmic rays regulate the level of ionization that controls not only the chemistry of molecular clouds but also the coupling between the gas and the magnetic field which support the cloud against gravity during the process of star formation. Interestingly, the ionization rates inferred from infrared and radio observations are much larger than the commonly quoted value in the literature. This calls for a reassessment from a theoretical point of view of the ionization rate in clouds. This task requires a better understanding of the transport of cosmic rays into clouds and, more importantly, the knowledge of the amount of low energy cosmic rays at different positions in our Galaxy. The former has been investigated in some of the pioneering papers in the seventies and eighties but there might be room for some improvements. The latter is known not too long ago at least for the local interstellar medium thanks to the data from the Voyager probes. It is, however, not very clear whether or not these data could be considered as reference values for the density of low energy cosmic rays in the entire Galaxy. The aim of this work is, therefore, to study the propagation of low energy cosmic rays in neutral environments and also to better interpret the observational data of the ionization rate in both isolated molecular clouds and the ones in the vicinity of cosmic accelerators like supernova remnants.
Author: Vo Hong Minh Phan Publisher: ISBN: Category : Languages : en Pages : 0
Book Description
It has been revealed by observational evidences from various experiments at the beginning of the 20th century that the Earth is constantly bombarded by cosmic rays, high-energy particles of extraterrestrial origin. Since these particles are very energetic, it is believed that they could penetrate deep into molecular clouds and ionize the densest parts of these objects where new stars are born. This means that cosmic rays regulate the level of ionization that controls not only the chemistry of molecular clouds but also the coupling between the gas and the magnetic field which support the cloud against gravity during the process of star formation. Interestingly, the ionization rates inferred from infrared and radio observations are much larger than the commonly quoted value in the literature. This calls for a reassessment from a theoretical point of view of the ionization rate in clouds. This task requires a better understanding of the transport of cosmic rays into clouds and, more importantly, the knowledge of the amount of low energy cosmic rays at different positions in our Galaxy. The former has been investigated in some of the pioneering papers in the seventies and eighties but there might be room for some improvements. The latter is known not too long ago at least for the local interstellar medium thanks to the data from the Voyager probes. It is, however, not very clear whether or not these data could be considered as reference values for the density of low energy cosmic rays in the entire Galaxy. The aim of this work is, therefore, to study the propagation of low energy cosmic rays in neutral environments and also to better interpret the observational data of the ionization rate in both isolated molecular clouds and the ones in the vicinity of cosmic accelerators like supernova remnants.
Author: Diego F. Torres Publisher: Springer Science & Business Media ISBN: 3642354106 Category : Science Languages : en Pages : 500
Book Description
These are the proceedings of the Sant Cugat Forum 2nd Workshop on Cosmic-ray Induced Phenomenology in Stellar Environments, held April 16-19, 2012. The aim of this Workshop was to address the current knowledge and challenges of high-energy emission from stellar environments at all scales and provide a comprehensive review of the state of the field from the observational to the theoretical perspectives. In the meeting, the prospects for possible observations with planned instruments across the multi-wavelength spectrum were analyzed and also how they impact on our understanding of these systems.
Author: P.K.F. Grieder Publisher: Elsevier ISBN: 0080530052 Category : Science Languages : en Pages : 1117
Book Description
In 1912 Victor Franz Hess made the revolutionary discovery that ionizing radiation is incident upon the Earth from outer space. He showed with ground-based and balloon-borne detectors that the intensity of the radiation did not change significantly between day and night. Consequently, the sun could not be regarded as the sources of this radiation and the question of its origin remained unanswered. Today, almost one hundred years later the question of the origin of the cosmic radiation still remains a mystery.Hess' discovery has given an enormous impetus to large areas of science, in particular to physics, and has played a major role in the formation of our current understanding of universal evolution. For example, the development of new fields of research such as elementary particle physics, modern astrophysics and cosmology are direct consequences of this discovery. Over the years the field of cosmic ray research has evolved in various directions: Firstly, the field of particle physics that was initiated by the discovery of many so-called elementary particles in the cosmic radiation. There is a strong trend from the accelerator physics community to reenter the field of cosmic ray physics, now under the name of astroparticle physics. Secondly, an important branch of cosmic ray physics that has rapidly evolved in conjunction with space exploration concerns the low energy portion of the cosmic ray spectrum. Thirdly, the branch of research that is concerned with the origin, acceleration and propagation of the cosmic radiation represents a great challenge for astrophysics, astronomy and cosmology. Presently very popular fields of research have rapidly evolved, such as high-energy gamma ray and neutrino astronomy. In addition, high-energy neutrino astronomy may soon initiate as a likely spin-off neutrino tomography of the Earth and thus open a unique new branch of geophysical research of the interior of the Earth. Finally, of considerable interest are the biological and medical aspects of the cosmic radiation because of it ionizing character and the inevitable irradiation to which we are exposed. This book is a reference manual for researchers and students of cosmic ray physics and associated fields and phenomena. It is not intended to be a tutorial. However, the book contains an adequate amount of background materials that its content should be useful to a broad community of scientists and professionals. The present book contains chiefly a data collection in compact form that covers the cosmic radiation in the vicinity of the Earth, in the Earth's atmosphere, at sea level and underground. Included are predominantly experimental but also theoretical data. In addition the book contains related data, definitions and important relations. The aim of this book is to offer the reader in a single volume a readily available comprehensive set of data that will save him the need of frequent time consuming literature searches.
Author: Edward L. Alpen Publisher: Academic Press ISBN: 0080540201 Category : Science Languages : en Pages : 517
Book Description
This newly revised and updated edition of Radiation Biophysics provides an in-depth description of the physics and chemistry of radiation and its effects on biological systems. Coverage begins with fundamental concepts of the physics of radiation and radioactivity, then progresses through the chemistry and biology of the interaction of radiation with living systems. The Second Edition of this highly praised text includes major revisions which reflect the rapid advances in the field. New material covers recent developments in the fields of carcinogenesis, DNA repair, molecular genetics, and the molecular biology of oncogenes and tumor suppressor genes. The book also includes extensive discussion of the practical impact of radiation on everyday life. - Covers the fundamentals of radiation physics in a manner that is understandable to students and professionals with a limited physics background - Includes problem sets and exercises to aid both teachers and students - Discusses radioactivity, internally deposited radionuclides, and dosimetry - Analyzes the risks for occupational and non-occupational workers exposed to radiation sources
Author: Lev Dorman Publisher: Springer Science & Business Media ISBN: 1402021135 Category : Science Languages : en Pages : 891
Book Description
The present monograph as well as the next one (Dorman, M2005) is a result of more than 50 years working in cosmic ray (CR) research. After graduation in December 1950 Moscow Lomonosov State University (Nuclear and Elementary Particle Physics Division, the Team of Theoretical Physics), my supervisor Professor D. I. Blokhintsev planned for me, as a winner of a Red Diploma, to continue my education as an aspirant (a graduate student) to prepare for Ph. D. in his very secret Object in the framework of what was in those time called the Atomic Problem. To my regret the KGB withheld permission, and I, together with other Jewish students who had graduated Nuclear Divisions of Moscow and Leningrad Universities and Institutes, were faced with a real prospect of being without any work. It was our good fortune that at that time there was being brought into being the new Cosmic Ray Project (what at that time was also very secret, but not as secret as the Atomic Problem), and after some time we were directed to work on this Project. It was organized and headed by Prof. S. N. Vernov (President of All-Union Section of Cosmic Rays) and Prof. N. V. Pushkov (Director of IZMIRAN); Prof. E. L. Feinberg headed the theoretical part of the Project.
Author: L.I. Miroshnichenko Publisher: Springer Science & Business Media ISBN: 9401596468 Category : Science Languages : en Pages : 489
Book Description
It turned out to be really a rare and happy occasion that we know exact1y when and how a new branch of space physics was born, namely, a physics of solar cosmic rays. It happened on February 28 and March 7, 1942 when the fIrst "cosmic ray bursts" were recorded on the Earth, and the Sun was unambiguously identifIed for the fIrst time as the source of high-velocity 10 particles with energies up to > 10 eV. Just due to such a high energy these relativistic particles have been called "solar cosmic rays" (SCR), in distinction from the "true" cosmic rays of galactic origin. Between 1942 and the beginning ofthe space era in 1957 only extremely high energy solar particle events could be occasionally recorded by cosmic ray ground-Ievel detectors and balloon borne sensors. Since then the detection techniques varied considerably and the study of SCR turned into essential part of solar and solar-terrestrial physics.
Author: Publisher: ISBN: Category : Languages : en Pages : 0
Book Description
High quality gamma-ray and radio observations of nearby galaxies offer an unprecedented opportunity to quantitatively study the properties of their cosmic ray populations. Accounting for various interactions and energy losses, I developed a multi-component, single-zone model of the cosmic ray populations in the central molecular zones of star-forming galaxies. Using observational knowledge of the interstellar medium and star formation, I successfully predicted the radio, gamma-ray, and neutrino spectra for nearby starbursts. Using chi-squared tests to compare the models with observational radio and gamma-ray data, I placed constraints on magnetic field strengths, cosmic ray energy densities, and galactic wind (advection) speeds. The initial models were applied to and tested on the prototypical starburst galaxy M82. To further test the model and to explore the differences in environment between starbursts and active galactic nuclei, I studied NGC 253 and NGC 1068, both nearby giant spiral galaxies which have been detected in gamma-rays. Additionally, I demonstrated that the excess GeV energy gamma-ray emission in the Galactic Center is likely not diffuse emission from an additional population of cosmic rays accelerated in supernova remnants. Lastly, I investigated cosmic ray populations in the starburst nuclei of Arp 220, a nearby ultraluminous infrared galaxy which displays a high-intensity mode of star formation more common in young galaxies, and I showed that the nuclei are efficient cosmic-ray proton calorimeters.
Author: Veniamin Sergeevich Berezinskiĭ Publisher: Elsevier Science & Technology ISBN: Category : Science Languages : en Pages : 556
Book Description
This book is devoted to the astrophysics of cosmic rays, especially the origin of the cosmic rays observed on Earth. The problem of the propagation and acceleration of cosmic rays in the interstellar medium and, in general, in the galaxy is discussed. Topics of gamma- and X-ray astronomy and of high-energy neutrino astronomy related to cosmic rays are also discussed. Summaries of the observational and experimental results are given."
Author: Penelope J. Allisy-Roberts Publisher: Elsevier Health Sciences ISBN: 0702028444 Category : Medical Languages : en Pages : 216
Book Description
This title is directed primarily towards health care professionals outside of the United States. The new edition has been fully updated to reflect the latest advances in technology and legislation and the needs of today's radiology trainees. Invaluable reading, particularly for those sitting the primary and final examinations of the Royal College of Radiology, UK, the book will also be of value to radiographers and personnel interested in medical imaging. The concise text is also accompanied by clear line drawings and sample images to illustrate the principles discussed. Closely matches needs of FRCR examination candidates. Updated to reflect changes to FRCR examination. More medically orientated. Covers new legislation concerning radiological safety etc. 'Must-know' summaries at end of each chapter. Completely new design.
Author: Olga E Malandraki Publisher: ISBN: 9781013270055 Category : Science Languages : en Pages : 208
Book Description
Solar energetic particles (SEPs) emitted from the Sun are a major space weather hazard motivating the development of predictive capabilities. This book presents the results and findings of the HESPERIA (High Energy Solar Particle Events forecasting and Analysis) project of the EU HORIZON 2020 programme. It discusses the forecasting operational tools developed within the project, and presents progress to SEP research contributed by HESPERIA both from the observational as well as the SEP modelling perspective. Using multi-frequency observational data and simulations HESPERIA investigated the chain of processes from particle acceleration in the corona, particle transport in the magnetically complex corona and interplanetary space, to the detection near 1 AU. The book also elaborates on the unique software that has been constructed for inverting observations of relativistic SEPs to physical parameters that can be compared with space-borne measurements at lower energies. Introductory and pedagogical material included in the book make it accessible to students at graduate level and will be useful as background material for Space Physics and Space Weather courses with emphasis on Solar Energetic Particle Event Forecasting and Analysis. This work was published by Saint Philip Street Press pursuant to a Creative Commons license permitting commercial use. All rights not granted by the work's license are retained by the author or authors.
Author: Vo Hong Minh Phan
Author: Vo Hong Minh Phan
Author: Diego F. Torres
Author: P.K.F. Grieder
Author: Edward L. Alpen
Author: Lev Dorman
Author: L.I. Miroshnichenko
Author: 
Author: Veniamin Sergeevich Berezinskiĭ
Author: Penelope J. Allisy-Roberts
Author: Olga E Malandraki