Download or read book Lightning Initiation Due to Hydrometeor Collisions in Thunderclouds written by Qiheng Cai and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In order to initiate streamers and leaders under thunderstorm conditions, the electric field should reach values higher than the critical breakdown field. However, the maximum electric field in thunderstorms measured by balloons is much smaller than the breakdown field. In order to investigate the electric field amplification required for streamer initiation in thunderclouds, in this dissertation work, we introduce two numerical models of two hydrometeors in uniform electric fields.The first model is two separated spherical hydrometeors. We have found the relationship between minimum electric field required for streamer initiation and the particle radius. The larger the radius, the lower electric field required. Furthermore, we consider the model of two particles with different radii for streamer initiation including the process of photoionization feedback, which could initially produce photons and then trigger a secondary electron avalanche to reduce the threshold electric field required for streamer initiation. The relationship between radii of particles for successful streamer initiation in the gap is investigated. We also demonstrate that for realistic particle dimensions, the avalanche to streamer transition is possible in a local electric field just slightly above the minimum field required for propagation of positive streamers in air.Considering that the connection of two spheres would lead to increase of the electric field at the outer periphery, and outside space represents a larger volume available for the photoionization feedback in comparison with the relatively small gap between two spheres, the second model of two spherical particles connected with a discharge channel is investigated. We also investigate the relationship of the radii of these two particles for streamer initiation on the outside periphery. Furthermore, we estimated the frequency of streamer initiation using three realistic hydrometeor size model distributions available in the literature and found that the scenario of streamer initiation on the outside periphery is only possible for relatively high electric fields, which are close to half of the breakdown electric field, at typical thundercloud altitudes of 3 and 6 km.
Download or read book Lightning Initiation in Thunderclouds written by J. Latham and published by . This book was released on 1983 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experiments have been carried out to determine the electric field, E sub c, required to obtain corona from both ice particles and cooling drop-pairs. In the former case it was found that corona currents of about 0.1 microA and above could be obtained from ice particles a few millimetres in length for C sub c approx. 4 x 100,000 V/m for values of temperature and pressure likely to occur in the mid-regions of a thundercloud. These currents were drastically reduced if temperature was below -18 deg C, owing to the reduction in surface conductivity suffered by the ice sample. In the second set of experiments, a pair of water drops, of radii R=2.7mm and r=0.65mm, collided with a relative velocity of 5.8m/s. Values of Ec ranged from approx. 500,000 m/s for head-on collisions to approx. 250,000 m/s for glancing collisions which produce, momentarily, long liquid filaments. (Author).
Download or read book Initiation of Streamers from Thundercloud Hydrometeors and Implications to Lightning Initiation written by Samaneh Sadighi and published by . This book was released on 2015 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: Electric field values measured inside thunderclouds have consistently been reported to be up to an order of magnitude lower than the value required for the conventional electrical breakdown of air. This result has made it difficult to explain how lightning frequently occurs in thunderclouds. A few different theories have been offered to explain the lightning initiation process, one of them being the theory of lightning initiation from hydrometeors. According to this theory, lightning can be initiated from electrical discharges originating around thundercloud water or ice particles in the measured thundercloud electric field. These particles, called hydrometeors, can cause significant enhancement of the thundercloud electric field in their vicinity, increasing the probability to initiate streamers that are precursor discharges for the hot lightning leader channel. The first step in improving our understanding of lightning initiation is to study streamers. For this dissertation research, we have focused our efforts on studying streamer initiation and propagation from thundercloud hydrometeors. For the first part of this study, we have further investigated the idea proposed by Liu et al. [2012b] to study streamers from ionization column hydrometeors in thundercloud conditions. We have performed simulations for ambient electric field values of 0.5E[k] at thundercloud altitudes, and obtained successful streamer formation, confirming the work of Liu et al. [2012bJ. Reducing the ambient electric field to as low as 0.3E[k] affects the streamer's ability to propagate stably. According to our results, initiation of stable streamers from thundercloud hydrometeors in a 0.3E[k] electric field is possible, only if enhanced ambient ionization levels (e.g., the ionization created by corona discharges around the same or other nearby hydrometeors) are present ahead of the streamer. The magnitude and distribution of this ambient density may be a determining factor on whether the streamer forms, or branches during initiation. The branching of the streamer interrupts the stable streamer propagation and changes the dynamics of the streamer. We investigate the streamer branching behavior and characteristics, and test a theory that has recently been proposed to explain this phenomenon [Savel'eva et al., 2013]. We find that the geometry of the streamer head plays an important role in the streamer branching phenomena. The fast radial movement of the maximum streamer head curvature, combined with the slow reduction of the maximum curvature value, eventually leads the streamer head to branching. In order to verify whether an ionization column is a proper representation of a dielectric hydrometeor, for the second part of this dissertation we modify our streamer discharge model to accommodate an isolated dielectric particle representing the hydrometeor inside the computational region. Since the governing equations of the plasma discharge model are discretized on a uniform rectangular grid, the boundary cells do not conform to the shape of the dielectric. We utilize a boundary-cut cell method proposed by Ye et al. [1999] to handle these cut cells, and properly evaluate the corresponding fluxes. A boundary condition capturing method by Liu et al. [2000] has been used to properly enforce the electrostatic boundary conditions on the dielectric hydrometeor. The development of this model has enabled us to accurately simulate the discharges around dielectric hydrometeors with various shapes and physical states. Streamer discharge results obtained from the dielectric hydrometeor have been presented and compared with the results obtained from the first part of this work. We compare our modeling results with laboratory experiments and realistic thundercloud conditions and discuss the implications of this study to lightning initiation and other lightning related phenomena.
Download or read book Fundamentals of Lightning written by Vladimir A. Rakov and published by Cambridge University Press. This book was released on 2016-04-07 with total page 271 pages. Available in PDF, EPUB and Kindle. Book excerpt: This new book provides a focused set of topics suitable for advanced undergraduate or graduate courses on lightning. It presents the current state of the art in lightning science including areas such as lightning modeling, calculation of lightning electromagnetic fields, electromagnetic methods of lightning location, and lightning damaging effects and protective techniques. Pedagogical features designed to facilitate class learning include end-of-chapter summaries, further reading suggestions, questions and problems, and a glossary explaining key lightning and atmospheric electricity terms. A selection of appendices are provided at the end of the book, which include detailed derivations of exact equations for computing electric and magnetic fields produced by lightning. Designed for a single-semester course on lightning and its effects, and written in a style accessible to technical non-experts, this book will also be a useful, up-to-date reference for scientists, engineers and practitioners who have to deal with lightning in their work.
Download or read book A Possible Effect of Lightning Initiation on Thundercloud Precipitation Development written by Christopher Thomas Phelps and published by . This book was released on 1975 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Lightning Principles Instruments and Applications written by Hans Dieter Betz and published by Springer Science & Business Media. This book was released on 2008-12-04 with total page 641 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lightning represents a natural phenomenon of substantial interest. Due to its complex nature, research continues in many countries and reveals amazing results. Lightning is actively observed because of its relevance to Earth climate and air composition in addition to the classical aspects of related human fatalities and damage to forests, buildings, power lines, aircraft, structures and electronic devices. In this volume, the most important contemporary questions on lightning are addressed and analyzed under many experimental and theoretical aspects. Lightning detection techniques using ground-based and space-borne methods are described, along with network engineering and statistical analysis. Contributions detail research on atmospheric electricity, cloud physics, lightning physics, modeling of electrical storms and middle atmospheric events. Special phenomena such as triggered lightning and sprite observations are examined. Lightning-induced nitrogen oxides and their effects on atmospheric chemistry and climate are discussed. Each topic is presented by international experts in the field. Topics include: * air chemistry * convective storms * infrasound from lightning * lightning and climate change * lightning and precipitation * lightning and radiation * lightning and supercells * lightning and thunderstorms * lightning detection * lightning from space * lighting protection * lightning return strokes * observations and interpretations * spatial distribution and frequency * triggered lightning * weather extremes
Download or read book The Problem of Lightning Initiation and a Related Laboratory Investigation of Positive Streamer Discharges from Simulated Ice Hydrometeors written by Danyal Allen Petersen and published by . This book was released on 2003 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Electrical Processes in Atmospheres written by H. Dolezalek and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 875 pages. Available in PDF, EPUB and Kindle. Book excerpt: These Proceedings are published to give a full account of the Fifth International Conference on Atmospheric Electricity held in September 1974 in Garmisch-Partenkirchen in the Bavarian Alps in Germany. Traditionally, the Proceedings of these Conferences have served as reference books updating the textbooks and monographs on Atmospheric Electricity. As treated by these Conferences, Atmos pheric Electricity covers all aspects of this science, including the processes and problems which reach out into the Earth's environment as well as analogous processes on other planets and on the Moon. A history of these Conferences, an account of their purpose, and an outline of the scope and the preparation is to be found at the end of these Proceedings. There, also the Business Meetings of the involved organizations are mentioned. The Proceedings closely follow the original program and are accordingly organized into "Sessions". The papers printed in each "Session" in this book are the ones which were accepted for the sessions of the Conference with the same numbers and titles. Only the two "Special Sessions" have been given different numbers in the Proceedings, i.e. 2a and 10. In principle, all papers which were accepted by the Executive Panel either for full oral presentation or for printing in the Proceedings only, have in fact been included in these Proceedings, whether they were presented or not. In the latter case, a special note is made to explain the absence of a discussion.
Download or read book 1998 Freshman Achievement Award written by David R. Lide and published by CRC Press. This book was released on 2003-06-19 with total page 2698 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides chemical and physical data.
Download or read book Proceedings of the 1992 International Aerospace and Ground Conference on Lightning and Static Electricity written by and published by . This book was released on 1992 with total page 678 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Clouds Rain and Rainmaking written by B. J. Mason and published by Cambridge University Press. This book was released on 1975-11-27 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dr Mason has revised and updated his popular account of cloud-related meteorological phenomena.
Download or read book The Electrical Nature of Storms written by D. R. MacGorman and published by Oxford University Press, USA. This book was released on 1998 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rapid progress during the last twenty years has created a host of new technologies for studying electrical storms, including lightning mapping systems, new radars, satellite sensors, and new ways of measuring electric field and particle charge. This book explains how these advances have revolutionized our understanding. The books provides substantial background material, making it accessible to a broad scientific audience.
Download or read book Encyclopedia of Atmospheric Sciences written by Gerald R. North and published by Elsevier. This book was released on 2014-09-14 with total page 2874 pages. Available in PDF, EPUB and Kindle. Book excerpt: Encyclopedia of Atmospheric Sciences, Second Edition, Six Volume Set is an authoritative resource covering all aspects of atmospheric sciences, including both theory and applications. With more than 320 articles and 1,600 figures and photographs, this revised version of the award-winning first edition offers comprehensive coverage of this important field. The six volumes in this set contain broad-ranging articles on topics such as atmospheric chemistry, biogeochemical cycles, boundary layers, clouds, general circulation, global change, mesoscale meteorology, ozone, radar, satellite remote sensing, and weather prediction. The Encyclopedia is an ideal resource for academia, government, and industry in the fields of atmospheric, ocean, and environmental sciences. It is written at a level that allows undergraduate students to understand the material, while providing active researchers with the latest information in the field. Covers all aspects of atmospheric sciences—including both theory and applications Presents more than 320 articles and more than 1,600 figures and photographs Broad-ranging articles include topics such as atmospheric chemistry, biogeochemical cycles, boundary layers, clouds, general circulation, global change, mesoscale meteorology, ozone, radar, satellite remote sensing, and weather prediction An ideal resource for academia, government, and industry in the fields of atmospheric, ocean, and environmental sciences
Download or read book Topical Problems of Nonlinear Wave Physics written by Alexander M. Sergeev and published by SPIE-International Society for Optical Engineering. This book was released on 2006 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt: Includes Proceedings Vol. 7821
Download or read book CRC Handbook of Chemistry and Physics written by William M. Haynes and published by CRC Press. This book was released on 2011-06-06 with total page 2624 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mirroring the growth and direction of science for a century, the CRC Handbook of Chemistry and Physics, now in its 92nd edition, continues to be the most accessed and respected scientific reference in the world, used by students and Nobel Laureates. Available in its traditional print format, the Handbook is also available as an innovative interactive product on DVD and online. Among a wealth of enhancements, this edition analyzes, updates, and validates molecular formulas and weights, boiling and melting points, densities, and refractive indexes in the Physical Constants of Organic Compounds Table through comparisons with critically evaluated data from the NIST Thermodynamics Research Center. New Tables: Analytical Chemistry Abbreviations Used In Analytical Chemistry Basic Instrumental Techniques of Analytical Chemistry Correlation Table for Ultraviolet Active Functionalities Detection of Outliers in Measurements Polymer Properties Second Virial Coefficients of Polymer Solutions Updated Tables: Properties of the Elements and Inorganic Compounds Update of the Melting, Boiling, Triple, and Critical Points of the Elements Fluid Properties Major update and expansion of Viscosity of Gases table Major update and expansion of Thermal Conductivity of Gases table Major update of Properties of Cryogenic Fluids Major update of Recommended Data for Vapor-Pressure Calibration Expansion of table on the Viscosity of Liquid Metals Update of Permittivity (Dielectric Constant) of Gases table Added new refrigerant R-1234yf to Thermophysical Properties of Selected Fluids at Saturation table Molecular Structure and Spectroscopy Major update of Atomic Radii of the Elements Update of Bond Dissociation Energies Update of Characteristic Bond Lengths in Free Molecules Atomic, Molecular, and Optical Physics Update of Electron Affinities Update of Atomic and Molecular Polarizabilities Nuclear and Particle Physics Major update of the Table of the Isotopes Properties of Solids Major update and expansion of the Electron Inelastic Mean Free Paths table Update of table on Semiconducting Properties of Selected Materials Geophysics, Astronomy, and Acoustics Update of the Global Temperature Trend table to include 2010 data Health and Safety Information Major update of Threshold Limits for Airborne Contaminants The Handbook is also available as an eBook.
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.
