Download or read book Numerical Modeling of Leader Discharge Mechanisms in Lightning Blue Jets Gigantic Jets and Sprites written by Caitano Da Silva and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The work presented in this dissertation is dedicated to the investigation of leader discharge mechanisms in lightning and transient luminous events. We introduce two new numerical models of the leader process that capture its onset and propagation, as briefly described below.The first theoretical model simulates air heating and streamer-to-leader transition in gas discharges. The model accounts for all physical processes known to play a role in the conversion of a streamer corona to a leader channel. Detailed discussion on the role of electron detachment in the development of the thermal-ionizational instability that triggers the spark development in short air gaps is presented. The dynamics of fast heating by quenching of excited electronic states is discussed and the scaling of its main channels with ambient air density is quantified. The developed model is employed to study the streamer-to-leader transition process and to obtain its scaling with ambient air density. The introduced methodology for estimation of leader speeds is based on the assumption that the propagation of a leader is limited by the air heating of every newly-formed leader section. It is demonstrated that the streamer-to-leader transition time has an inverse-squared dependence on the ambient air density at near-ground pressures, in agreement with similarity laws for Joule heating in a streamer channel. Model results indicate that a deviation from this similarity scaling occurs at very-low air densities, where the rate of electronic power deposition is balanced by the channel expansion, and air heating from quenching of excited electronic states is very inefficient. These findings place a limit on the maximum altitude at which a hot and highly-conducting lightning leader channel can be formed in the Earth's atmosphere. This result is important for understating of the gigantic jet discharges between thundercloud tops and the lower ionosphere. Our simulations of leader propagation at stratospheric altitudes demonstrate that initial speeds of gigantic jets are consistent with the leader propagation mechanism, and that the observed acceleration in gigantic jets can be attributed to the expansion of its streamer zone in a medium of exponentially-decreasing air density. This process defines the existence of an altitude at which the streamer zone becomes so long that it dynamically extends all the way to the ionosphere. We extend the air heating model to simulate the effects of strong currents flowing in sprites in the mesosphere. We show that fast air heating (due to quenching of excited electronic states) in sprite cores can produce >0.01 Pa pressure perturbations on the ground, observed in association with sprites. The second theoretical model simulates the electromagnetic radiation generated during the initial breakdown stage of lightning discharges. We use this model to describe in detail how the leader discharge dynamics generates the so-called initial breakdown pulses (IBPs) and narrow bipolar events (NBEs) observed with multi-station electric field change sensors on the ground. IBPs have been correlated with individual bursts of light that appear to be illuminations of a lightning leader channel; as a flash evolves the location of IBP sources inside the cloud coincides with the position of negative leaders as determined by a VHF lightning mapping system. NBEs are electric field signatures with broadband waveforms resembling classic IBPs in both amplitude and duration. Nonetheless, NBEs are quite peculiar in the sense that very infrequently they are followed by conventional lightning processes. Only a small fraction of positive-polarity NBEs happen as the first event in an otherwise regular intracloud lightning discharge. Typically, the initiator-type of NBEs has no difference with other NBEs that did not start lightning, except for the fact that they occur deeper inside the thunderstorm (i.e., at lower altitudes). In this dissertation we propose that IBPs and NBEs are the electromagnetic transients associated with the sudden (i.e., stepwise) elongation of the initial negative leader extremity in the thunderstorm electric field. To demonstrate our hypothesis we use a novel model of the leader electrodynamics. It consists of a generalization of electrostatic and transmission-line approximations existing in the refereed literature. We demonstrate how the IBP and NBE waveform characteristics directly reflect the properties of the bidirectional lightning leader (such as step length, for example) and amplitude of the thunderstorm electric field.
Download or read book Sprites Elves and Intense Lightning Discharges written by Martin Füllekrug and published by Springer Science & Business Media. This book was released on 2006-05-27 with total page 399 pages. Available in PDF, EPUB and Kindle. Book excerpt: Particularly intense lightning discharges can produce transient luminous events above thunderclouds, termed sprites, elves and jets. These short lived optical emissions in the mesosphere can reach from the tops of thunderclouds up to the ionosphere; they provide direct evidence of coupling from the lower atmosphere to the upper atmosphere. Sprites are arguably the most dramatic recent discovery in solar-terrestrial physics. Shortly after the first ground based video recordings of sprites, observations on board the Space Shuttle detected sprites and elves occurring all around the world. These reports led to detailed sprite observations in North America, South America, Australia, Japan, and Europe. Subsequently, sprites were detected from other space platforms such as the International Space Station and the ROCSAT satellite. During the past 15 years, more than 200 contributions on sprites have been published in the scientific literature to document this rapidly evolving new research area.
Download or read book Techniques for Disaster Risk Management and Mitigation written by Prashant K. Srivastava and published by John Wiley & Sons. This book was released on 2020-05-27 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive guide to managing and mitigating natural disasters Recent years have seen a surge in the number, frequency, and severity of natural disasters, with further increases expected as the climate continues to change. However, advanced computational and geospatial technologies have enabled the development of sophisticated early warning systems and techniques to predict, manage, and mitigate disasters.Techniques for Disaster Risk Management and Mitigation explores different approaches to forecasting disasters and provides guidance on mitigation and adaptation strategies. Volume highlights include: Review of current and emerging technologies for disaster prediction Different approaches to risk management and mitigation Strategies for implementing disaster plans and infrastructure improvements Guidance on integrating artificial intelligence with GIS and earth observation data Examination of the regional and global impacts of disasters under climate variability
Download or read book Lightning written by Chandima Gomes and published by Springer Nature. This book was released on 2021-08-13 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book highlights the essential theoretical and practical aspects of lightning, lightning protection, safety and education. Additionally, several auxiliary topics that are required to understand the core themes are also included. The main objective of the contents is to enlighten the scientists, researchers, engineers and social activists (including policy makers) in developing countries regarding the key information related to lightning and thunderstorms. A majority of developing countries are in tropics where the lightning characteristics are somewhat different from those in temperate regions. The housing structures and power/communication networks, and human behavioural patterns(that depends on socio-economic parameters) in these countries are also different from those in the developed world. As the existing books on similar themes address only those scenarios in developed countries, this book serves a vast spectrum of readership in developing world who seek knowledge in the principles of lightning and a practical guidance on lightning protection and safety education.
Download or read book Lightning written by Vladimir A. Rakov and published by Cambridge University Press. This book was released on 2007-01-08 with total page 1485 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lightning: Physics and Effects is the first book that covers essentially all aspects of lightning, including lightning physics, lightning protection and the interaction of lightning with a variety of objects and systems as well as with the environment. It is written in a style that will be accessible to the technical non-expert and is addressed to anyone interested in lightning and its effects. This will include physicists, engineers working in the power, communications, computer and aviation industries, meteorologists, atmospheric chemists, foresters, ecologists, physicians working in the area of electrical trauma and architects. This comprehensive reference volume contains over 300 illustrations, 70 tables containing quantitative information and a bibliography of more than 6000 references.
Download or read book An Introduction to Lightning written by Vernon Cooray and published by Springer. This book was released on 2014-10-08 with total page 391 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book about lightning summarizes the essence of physics and effects of lightning in a non-technical manner and provides an up-to-date description of the phenomenon of lightning in simple language. Starting with the myths related to lightning, the reader is introduced to the mechanism of lightning flashes and their interactions with humans, human-made systems and Earth’s environment. Most of the available books on lightning are written for the experts in the field and there is a need for a book that introduces the undergraduate and beginning post graduate students to the subject of lightning and prepares them for more advanced books meant for the experts. This introductory book, which is based on a series of lectures given to undergraduate and postgraduate students in electrical engineering, is intended to fill this need. Tailored to the needs of university students who plan to study electrical engineering, meteorology, environmental or basic physics, it is also a valuable reference resource for laymen who are interested in knowing more on this phenomenon.
Download or read book Spatial Augmented Reality written by Oliver Bimber and published by CRC Press. This book was released on 2005-08-08 with total page 386 pages. Available in PDF, EPUB and Kindle. Book excerpt: Like virtual reality, augmented reality is becoming an emerging platform in new application areas for museums, edutainment, home entertainment, research, industry, and the art communities using novel approaches which have taken augmented reality beyond traditional eye-worn or hand-held displays. In this book, the authors discuss spatial augmented r
Download or read book Cold Plasma in Food and Agriculture written by NN Misra and published by Academic Press. This book was released on 2016-07-15 with total page 382 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cold Plasma in Food and Agriculture: Fundamentals and Applications is an essential reference offering a broad perspective on a new, exciting, and growing field for the food industry. Written for researchers, industry personnel, and students interested in nonthermal food technology, this reference will lay the groundwork of plasma physics, chemistry, and technology, and their biological applications. Food scientists and food engineers interested in understanding the theory and application of nonthermal plasma for food will find this book valuable because it provides a roadmap for future developments in this emerging field. This reference is also useful for biologists, chemists, and physicists who wish to understand the fundamentals of plasma physics, chemistry, and technology and their biological interactions through applying novel plasma sources to food and other sensitive biomaterials. Examines the topic of cold plasma technology for food applications Demonstrates state-of-the-art developments in plasma technology and potential solutions to improve food safety and quality Presents a solid introduction for readers on the topics of plasma physics and chemistry that are required to understand biological applications for foods Serves as a roadmap for future developments for food scientists, food engineers, and biologists, chemists, and physicists working in this emerging field
Download or read book Planetary Atmospheric Electricity written by François Leblanc and published by Springer Science & Business Media. This book was released on 2008-12-04 with total page 373 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a comprehensive discussion of all issues related to atmospheric electricity in our solar system. It details atmospheric electricity on Earth and other planets and discusses the development of instruments used for observation.
Download or read book Infrasound Monitoring for Atmospheric Studies written by Alexis Le Pichon and published by Springer Science & Business Media. This book was released on 2010-01-19 with total page 739 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of infrasound to monitor the atmosphere has, like infrasound itself, gone largely unheard of through the years. But it has many applications, and it is about time that a book is being devoted to this fascinating subject. Our own involvement with infrasound occurred as graduate students of Prof. William Donn, who had established an infrasound array at the Lamont-Doherty Geological Observatory (now the Lamont-Doherty Earth Observatory) of Columbia University. It was a natural outgrowth of another major activity at Lamont, using seismic waves to explore the Earth’s interior. Both the atmosphere and the solid Earth feature velocity (seismic or acoustic) gradients in the vertical which act to refract the respective waves. The refraction in turn allows one to calculate the respective background structure in these mediums, indirectly exploring locations that are hard to observe otherwise. Monitoring these signals also allows one to discover various phenomena, both natural and man-made (some of which have military applications).
Download or read book The Periodic Table written by Primo Levi and published by Everyman's Library. This book was released on 1996-10-01 with total page 279 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Periodic Table is largely a memoir of the years before and after Primo Levi’s transportation from his native Italy to Auschwitz as an anti-Facist partisan and a Jew. It recounts, in clear, precise, unfailingly beautiful prose, the story of the Piedmontese Jewish community from which Levi came, of his years as a student and young chemist at the inception of the Second World War, and of his investigations into the nature of the material world. As such, it provides crucial links and backgrounds, both personal and intellectual, in the tremendous project of remembrance that is Levi’s gift to posterity. But far from being a prologue to his experience of the Holocaust, Levi’s masterpiece represents his most impassioned response to the events that engulfed him. The Periodic Table celebrates the pleasures of love and friendship and the search for meaning, and stands as a monument to those things in us that are capable of resisting and enduring in the face of tyranny.
Download or read book Photoionization And Photodetachment In 2 Parts written by Cheuk-yiu Ng and published by World Scientific. This book was released on 2000-06-30 with total page 684 pages. Available in PDF, EPUB and Kindle. Book excerpt: Owing to the advances of vacuum ultraviolet and ultrafast lasers and third generation synchrotron sources, the research on photoionization, photoelectrons, and photodetachment has gained much vitality in recent years. These new light sources, together with ingenious experimental techniques, such as the coincidence imaging, molecular beam, pulsed field ionization photoelectron, mass-analyzed threshold ion, and pulsed field ion pair schemes, have allowed spectroscopic, dynamic, and energetic studies of gaseous species to a new level of detail and accuracy. Profitable applications of these methods to liquids are emerging.This invaluable two-volume review consists of twenty-two chapters, focusing on recent developments in photoionization and photodetachment studies of atoms; molecules, transient species, clusters, and liquids.
Download or read book Practical Meteorology written by Roland Stull and published by Sundog Publishing, LLC. This book was released on 2018 with total page 942 pages. Available in PDF, EPUB and Kindle. Book excerpt: A quantitative introduction to atmospheric science for students and professionals who want to understand and apply basic meteorological concepts but who are not ready for calculus.
Download or read book Generation and Applications of Extra Terrestrial Environments on Earth written by Daniel A. Beysens and published by CRC Press. This book was released on 2022-09-01 with total page 317 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book has been prepared under the auspice of the European Low Gravity Research Association (ELGRA). The main task of ELGRA is to foster the scientific community in Europe and beyond in conducting gravity and space-related research.This publication is dedicated to the science community, and especially to the next generation of scientists and engineers interested in space research and in the means to use Earth to reproduce the space environment. ELGRA provides a comprehensive description of space conditions and the means that have been developed on Earth to perform space environmental and (micro-) gravity related research. .The book covers ground-based research instruments and environments for both life and physical sciences research. It discusses the opportunities and limitations of protocols and instruments to compensate gravity or simulate microgravity, such as clinostats, random positioning machines, levitating magnets, electric fields, vibrations, tail suspension or head down tilt, as well as centrifuges for hyper-g studies. Other space environmental conditions are addressed too, like cosmic radiation or Mars atmospheric and soil properties to be replicated and simulated on Earth. Future long duration of manned missions, personal well-being and crew interaction are major issues dealt with.
Download or read book Lost Science written by Gerry Vassilatos and published by . This book was released on 2000 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rediscover the legendary names of a suppressed scientific revolution -- remarkable lives, astounding discoveries, and incredible inventions which would have produced a world of wonder. Each chapter is a biographic treasure. Ours is a world living hundreds of years behind its intended stage of development. Complete knowledge of this loss is the key to recapturing this wonder technology. -- From publisher's description.
Download or read book Schumann Resonance for Tyros written by Alexander Nickolaenko and published by Springer Science & Business Media. This book was released on 2013-11-19 with total page 355 pages. Available in PDF, EPUB and Kindle. Book excerpt: Schumann resonance has been studied for more than half a century. The field became popular among researchers of the terrestrial environment using natural sources of electromagnetic radiation—lightning strokes, primarily—and now many Schumann observatories have been established around the world. A huge number of publications can be found in the literature, the most recent collection of which was presented in a special Schumann resonance section of the journal Radio Science in 2007. The massive publications, however, impede finding information about how to organize measurements and start observations of global electromagnetic resonance. Relevant information is scattered throughout many publications, which are not always available. The goal of this book is to collect all necessary data in a single edition in order to describe the demands of the necessary equipment and the field-site as well as the impact of industrial and natural interference, and to demonstrate typical results and obstacles often met in measurements. The authors not only provide representative results but also describe unusual radio signals in the extremely low-frequency (ELF) band and discuss signals in the adjacent frequency ranges.
Download or read book Chemical Kinetics Data Survey VII written by David Garvin and published by . This book was released on 1974 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt:
