Lightning Physics

Electric radiation fields produced by lightning cloud flashes have been analyzed using Fourier methods to obtain amplitude spectra for frequencies in the range of 20 kHz to 20 MHz. Time to thunder measurements were used to extract the distances to the cloud flashes from the measurement site. The spectra were generated by analyzing the first 10 ms time window of cloud flashes with 10 ns sampling resolution, and they show f-1 frequency dependence up to 2 MHz followed by f-2 dependence and higher for frequencies above 2 MHz. The results agree very well with previous measurements carried out for individual pulses produced by various lightning processes. By utilizing digital filters, it has been shown that measurements taken with narrowband filters agree with the results produced under wideband measurements

A physics-based model describing the thermal interaction between a lightning channel and a composite structure has been developed. The model includes: (i) spatial and temporal evolution of the lightning channel as a function of the electric current waveform; (ii) temporary and spatially non-uniform heat flux generated at the composite structure, where the heat flux is an explicit function of the electric current waveform and the instant lightning channel radius; (iii) nonlinear transient heat transfer problem formulation for layered anisotropic composites that accounts for temperature-dependent material properties,  a moving boundary of the expanding lightning channel, and phase transition moving boundary associated with instantaneous material removal due to sublimation. The model is applied for evaluation of thermal damage of the tip glass fiber reinforced polymer matrix composite panel of the Sandia 100-meter All-glass Baseline Wind Turbine Blade (SNL 100-00) subjected to lightning strike.

Here the readers can find basics of modern lightning protection technologies and essentials of grounding technics inlcuyding products and other devices manufactured by ORBITAL Lightning Protection.

Here are the details of working schedule and sketchs of ORBITAL LightninG Terminals with its technical aspects.

More cites and information for https://orbitaltechs.com

Lightning is a natural phenomenon in which large amounts of electricity are discharged from one location to another through open air, resulting in a bright arc of light. During an electrical storm, clouds begin to build up powerful electric fields, eventually ionizing the air around them and developing a powerful current. These areas, called step leaders, form paths of ionized air (or plasma) that slowly make their way toward the Earth. If a step leader makes contact with another ionized path, called a positive streamer, it creates a completed path for the plasma to travel on, allowing the accumulated current in the cloud to travel between the two points. This results in a lightning bolt and an explosion of air, which we call thunder. This project discusses the steps to design earthing and lightning protection system on building. The building is made strong and resistive against lightning strikes by making the building as negatively charged structure with use of cathodic protection materials and coatings. In addition, treating the problems that affects the structure gets reduced by lightning protection method which are determined by experiments and case studies.

The author presents an exciting new hypothesis for megafauna extinction based upon historical, mythical, geological, astronomic, and atmospheric evidence. While not conclusive, it is highly compelling and demands further investigation. Examples of cross cultural motifs in the form of glyphs, mounds, and earthworks are provided with mythic comparisons and contrasts. Counter arguments are provided throughout as well as strong debunking of prior archaeological biases rooted in Victorian, antiquated pseudoscience. Assumptions in the two models presented for plasma-arc-discharge mechanism are clearly listed, as well as known facts. Citations enable cross reference while the work focuses not on diffusion anthropology, but realistic atmospheric/astronomical plasmoid petroglyph formations recorded in rock

FRANKENSTEIN

Summary

Around the age of seven, Victor's younger brother is born. Up to this point, he and Elizabeth have been the primary receivers of their parents' love. Their parents decide to settle down in Geneva to concentrate on raising their family.

Victor introduces his life-long friend Henry Clerval, a creative child who studies literature and folklore.

At the age of 13, Victor discovers the works of Cornelius Agrippa, Paracelsus, and Albertus Magnus, all alchemists from an earlier age. His voracious appetite for knowledge thus begins, and eventually leads him to study science and alchemy. At age 15, Victor witnesses an electrical storm that peaks his interest in electricity and possible applications for its use.

Analysis

Victor tells how he and Elizabeth are brought up together as "there was not quite a year difference in our ages." He is serious and loud as a child, while Elizabeth has a more calm and subdued personality. The reader now sees a small glimpse of Victor's obsession with knowledge and learning. It is not unlike Mary Shelley's own lust for learning as a child and as the wife of Percy Shelley. Victor is the seeker of knowledge, "delighting in investigating their causes." He seeks answers to what occurs in nature and the physical world.

When Victor's parents return to Geneva to settle down, Victor is more solitary, doesn't like crowds, and finds himself alone at school. He befriends Henry Clerval, a Romantic character, who becomes his life-long pal. Henry is a writer and poet, a more creative person than the scientifically minded Victor. Henry is fascinated with the heroes of Roncesvalles, King Arthur and the Knights of the Round Table, and the knights of the Crusades.

We now begin to see Victor's personality type as sometimes "violent and my passions vehement." He dislikes learning languages, politics, and government and instead chooses to throw himself into the study of science, which he calls "the physical secrets of the world." While Elizabeth and Henry pursue the normal activities of children, Victor wants to learn all he can about the how's and why's of the world.

At the age of 13, Victor makes a discovery that forever changes his life. A storm confines him to remain inside one day where he discovers a volume of Cornelius Agrippa's works. His passion for learning leads him to Paracelsus and Albertus Magnus, two other scientists from earlier days, and invigorates Victor into a serious study of science and its possible applications. He reads science books for pleasure and knowledge, seeking to improve his mind and stimulate his curiosity. He laments that his father "was not scientific." Victor "was left to struggle with a child's blindness, added to a student's thirst for knowledge." He also exults, "The raising of ghosts or devils was a promise literally accorded by my favorite authors, the fulfillment of which I most eagerly sought." This gives us an idea of where he got the idea to create his own creature. He goes on to say that, "if my incantations were always unsuccessful, I attributed the failure rather to my own inexperience and mistake than to a want of skill or fidelity in my instructors." This seems to tell us that he wasn't having any luck with the teachings of his "instructors," so he knew that there must be another way, which opens up the possibility of using another science, electricity.

At age 15, Victor witnesses a summer thunderstorm that arouses his thoughts about electricity and possible applications for its use. The storm indirectly gives Victor the opportunity to learn more about technology and science. The storm Shelley describes is much like the one she and her fellow writers experience during the summer of 1816. Victor sees how the lightning has the power of destruction when a tree near their home is destroyed from a lightning strike. This confirms his belief that electricity and "galvanism" are worthy subjects for further study. A visitor in the Frankenstein home explains the phenomena to the young boy, and it facilitates a change in his thinking.

Although the details of the monster's creation are not described later in the book, Shelley hints that Victor uses his knowledge from the science books and of electricity to create his monster. Shelley makes Victor's interest in these topics very clear, so that the reader can deduce that he will use this knowledge in his creation.

Victor becomes a student of mathematics and pure science, seeking to learn the most he can, while abandoning his earlier study of well-known alchemists. His mind is not eased but spurred on by his lust for all knowledge and learning. He sees his fate as sealed after this choice in life saying:"Destiny was too potent, and her immutable laws had decreed my utter and terrible destruction."

Glossary

galvanism electricity produced by a chemical reaction.
campagne open country.
filial of, suitable to, or due from a son or daughter.
vehement having or characterized by intense feeling or strong passion; fervent, impassioned, etc.
predilection a preconceived liking; partiality or preference (for).
preceptors teachers.

Plasma (from Ancient Greek πλάσμα​ 'moldable substance') is one of the four fundamental states of matter, and was first described by chemist Irving Langmuir in the 1920s. It consists of a gas of ions – atoms which have some of their orbital electrons removed – and free electrons. Plasma can be artificially generated by heating a neutral gas or subjecting it to a strong electromagnetic field to the point where an ionized gaseous substance becomes increasingly electrically conductive. The resulting charged ions and electrons become influenced by long-range electromagnetic fields, making the plasma dynamics more sensitive to these fields than a neutral gas.

Plasma and ionized gases have properties and behaviours unlike those of the other states, and the transition between them is mostly a matter of nomenclature and subject to interpretation. Based on the temperature and density of the environment that contains a plasma, partially ionized or fully ionized forms of plasma may be produced. Neon signs and lightning are examples of partially ionized plasmas. The Earth's ionosphere is a plasma and the magnetosphere contains plasma in the Earth's surrounding space environment. The interior of the Sun ( which is btw much closer to earth than claimed ) is an example of fully ionized plasma, along with the solar corona and stars.

Positive charges in ions are achieved by stripping away electrons orbiting the atomic nuclei, where the total number of electrons removed is related to either increasing temperature or the local density of other ionized matter. This also can be accompanied by the dissociation of molecular bonds, though this process is distinctly different from chemical processes of ion interactions in liquids or the behaviour of shared ions in metals. The response of plasma to electromagnetic fields is used in many modern technological devices, such as plasma televisions or plasma etching.

Plasma may be the most abundant form of ordinary matter in the universe, although this hypothesis is currently tentative based on the existence and unknown properties of dark matter. Plasma is mostly associated with stars, extending to the rarefied intracluster medium and possibly the intergalactic regions

This paper investigates the existence of distinctive features between 4 different types of lightning discharges, namely negative cloud to ground discharge (-CG), positive cloud to ground discharge (+CG), cloud discharge (IC) and isolated breakdown discharge (IB). A total of 110 very fine structure waveforms of 44 -CG, 16 +CG, 39 IC, and 11 IB discharges have been selected from a collection of 885 waveforms measured using fast electric field broadband antenna system. The measurements were carried out in Uppsala, Sweden from May to August 2010. We found that there are significant distinctions within the first 1 ms among different types of lightning discharges (-CG, +CG, IC, and IB). For example, the pulses in -CG discharges are more frequent than other discharges; the pulses in +CG discharges have the highest intensity and the IC discharge pulses tend to have shorter duration.

Receptor plays an essential role in determining the efficiency of lightning strike protection on wind turbine blades. To investigate the effects of receptors with different shapes and sizes on the lightning strike protection, we apply five different receptor configurations to the blade of a high fidelity wind turbine model. The static electric field strength on the blade surfaces due to a lightning stepped leader is predicted through the development of a numerical model with finite element analysis. The interception efficiency is evaluated by comparing the predicted maximum electric field strength in the vicinity of the receptors.  In addition, the locations of the predicted lightning strike attachment points match well with those obtained by experimental measurements, which validate the current numerical approach.

(In English) Indonesia is a tropical country and an archipelago that has two seasons namely dry and rainy. In the rainy season often a lightning phenomenon that can endanger national resources. This condition needs to be minimized by the presence of lightning hazard information. This study aims to determine the lightning hazard information display. Service lightning BMKG information in this article shows that at certain times the lightning spread very evenly in the region of South Sumatra and Java. Service lightning hazard information is very useful to support the protection functions of national resources.

Keywords: lightning, protection, national resources, community welfare

(In Bahasa) Indonesia merupakan negara beriklim tropis dan berbentuk kepulauan yang memiliki dua musim yakni kemarau dan hujan. Pada musim hujan seringkali terjadi fenomena petir yang dapat membahayakan sumber daya nasional. Kondisi ini perlu diminimalisasi dengan adanya informasi bahaya petir. Studi ini bertujuan untuk mengetahui tampilan informasi bahaya petir. Metode yang digunakan dalam penelitian ini adalah kualitatif dengan pendekatan observasi. Layanan informasi petir BMKG pada artikel ini menunjukkan bahwa pada waktu-waktu tertentu sebaran petir sangat merata di wilayah Sumatra bagian Selatan dan Jawa. Layanan informasi bahaya petir ini sangat bermanfaat untuk mendukung fungsi proteksi sumber daya nasional.

Kata kunci: petir, proteksi, sumber daya nasional, kesejahteraan masyarakat

A primary motivation for this study comes from the need to improve the ability of polymer matrix composites to withstand lightning strikes. In particular, we are concerned with lightning strike damage in composite wind turbine blades. The problem is essentially multiphysic, as the electric-current-induced temperature in the composite blade subjected to a lightning strike may reach up to 1,200 °C, leading to extensive thermal damage including surface damage, delamination, cracks, matrix decomposition, fiber breakage and sublimation, and abrupt failure of the blade.   
In this work, the thermal response of the polymer-matrix composite laminate used in a Sandia 100-meter All-glass Baseline Wind Turbine Blade (SNL 100-00) subjected to lightning strike is studied. The tip region composite panel is considered, as it has been reported in the literature that the blade tip is more susceptible to lightning strike than the remaining parts of the blade.
A physical model to show the surface interaction between the lightning arc and the composite structure has been developed. The model provides time- and electric-current-dependent variation of the lightning arc radius and lightning-current-induced heat flux generated at the composite surface. The temperature-dependent thermal properties of the VectorPly E-LT 5500 unidirectional [0]2 E-glass fiber vinyl ester resin matrix fabric and SNL triaxial [±45]2[0]2 E-glass fiber vinyl ester resin matrix fabric used in the wind blade tip composite panel were derived using available experimental data. The formulated nonlinear transient heat transfer problem with moving boundary is solved using the finite element method. The solution procedure accounts for phase transitions in the materials, and the obtained results include temperature field profiles and evolution of the thermal damage.

This work is concerned with thermal ablation modeling in carbon fiber-reinforced polymer-matrix composite laminates subjected to the lightnig strike. Both direct heat injection and Joule heating produced by the lightning current are taken into account. First, a model describing interaction of the lightning current channel with a conductive structure is presented. The model includes channel expansion and spatial and temporal distribution of the lightning current and linghtning-induced heat flux. Second, anisotropic electrical and thermal properties of the CFRP composite laminates are determined in a wide temperature range (up to the sublimation temperature of the carbon fibers) using experimental data and micromechanics considerations. Third, a nonlinear thermo-electric coupled problem is formulated and solved for a CFRP composite laminate to determine the electric-current-induced temperature distribution and associated thermal ablation. Finally, the obtained predictions of thermal ablation in the CFRP composite laminate are compared to the reported experimental results. It is found that the predicted thermal ablation depths agree well with those reported in the experimental study.

In this paper, we investigate the wavelet characteristics of the first electric field pulse of four different flash types namely negative cloud-to-ground flash (-CG), positive cloud-to-ground flash (+CG), cloud flash (IC) and isolated breakdown flash (IB). A total 110 fine waveforms out of 885 were selected which have been recorded during summer between May and August 2010 in Uppsala, Sweden. The measurement was done by using an electric field broadband antenna system with the time resolution of 50 Megasample per second. Evidence from our wavelet analysis suggests that the ionization process during the initial leader development (coincide with the detection of the first electric field pulse) of at least three flashes (-CG, IC, and IB) in Sweden was dictated directly by the existence and magnitude of localized free ions region and lower positive charge center (p region). In general, we found that both single peak and multiple peaks pulses of the negative CG and IC flashes radiated energy at higher frequencies and gain larger bandwidth when compared to positive CG and IB flashes. We suggest that the initial leader development of both IC and negative CG flashes underwent very rapid and much more extensive ionization process when compared to the positive CG and IB flashes. In specific comparison between negative CG and IC flashes, both temporal and wavelet analyses suggest that the first electric field pulses of IC flash radiated energy at higher frequency in both single spread categories and radiated energy at lower frequency in both multiple spread categories when compared to the negative CG flash. This finding may explain the observation of much slower and less bright type  leader (ionization process not so extensive) compared to much faster and very bright type  leader (ionization process very rapid and more extensive). As for positive CG and IB flashes, the single peak pulses of positive CG radiated energy at much higher frequency while the multiple peaks pulses radiated energy at much lower frequency than IB flash. We suggest that the initiation mechanism of positive CG was dictated directly by the background electric field between the main positive charge centre and the ground, which is distinct from the initiation mechanism of IB flash. The presence of small magnitude of localized free ions region facilitated the rapidity of the ionization process in the initial leader development of IB flash.

Flow distributions in the heart and lung are heterogeneous but not at all random. The apparent degree of heterogeneity increases as one reduces the size of observable elements; the fact that the dispersion of flows shows a logarithmic relation to element size says that the system is statistically fractal. The fractal characterization is a statement that the system is nonrandom and that it shows correlation. The close near neighbor correlation has as the corollary of long tailing or falloff in correlation with distance, so called spatial persistence. Correlation can be expected because flow is delivered via a branching vascular system, and so it appears that the structure of the vasculature itself contributes. Since it is also practical and efficient for growth to occur via recursive rules, such as branch, grow, and repeat the branching and growing, it appears that fractals may be useful in understanding the ontological aspects of growth of tissues and organs, thereby minimizing the requirements for genetic material.

The GOES‐16 Geostationary Lightning Mapper (GLM) detection efficiency (DE) is studied over
a full year (2018/19) in central Florida using the Kennedy Space Center Lightning Mapping Array (KSC
LMA). Mean daily flash DE was 73.8%, and detection was highest during nighttime hours. GLM reported
86.5% of the LMA flashes that had coincident cloud‐to‐ground return strokes reported by the U.S. National
Lightning Detection Network. Results also reveal that flash size and duration are critical parameters
influencing GLM detection, regardless of the storm type, with 20–40% detection for small and short‐duration
flashes and greater than 95% detection for very large and long‐duration flashes.
These findings can be explained by examining the time‐evolution of cloud‐top optical emissions observed by
the Lightning Imaging Sensor (LIS). Statistical simulations based on long‐term LIS group area observations
indicate that about half of the above‐threshold light sources are smaller than a LIS pixel (~ 4 × 4 km)
and are smallest during and just after an initial breakdown in IC flashes. This work also demonstrates that
for sources smaller than a GLM pixel, the cloud‐top energy detection threshold for GLM is double that for
LIS despite GLM's lower energy density threshold. Overall, these findings provide a framework for
interpreting GLM performance under varying meteorological conditions, and help explain reports of low
flash detection efficiency for storms associated with severe weather, as they typically exhibit high flash rates
and resulting small and short‐duration flashes.

In this paper, the electric fields in the wind turbine blades due to the lightning stepped leader are studied and the dielectric breakdown is assessed. The developed finite element analysis (FEA) includes the full length of the leader and enables one to incorporate various uniform and non-uniform charge density models. The lightning striking distance is calculated using the rolling sphere method. The electric field in a horizontal axis wind turbine with three blades representing Sandia 100-meter All-glass Baseline Wind Turbine Blades (SNL 100-00) at three different lightning protection levels (LPL) is computed and compared to the dielectric breakdown strength of the blades. The dielectric breakdown strength of the blades is evaluated based on the experimental data. The results show that the tip region of the blade is the most vulnerable to the dielectric breakdown with the safety factor as low as 1.32 at LPL I.

We report synchronized optical observations of sprites in Israel during the winters of 2006/7–2007/8. Based on several events, we suggest that the elements of columniform sprites are organized in spaced intervals on the circumference of a circle centered directly above, or a little offset, to the vertical direction from the parent lightning. In 2D images most of the cases show columns to be arranged in highly eccentric elliptical forms or in straight rows. The analysis of the optical images provided the geometrical dimensions of the columns and their spatial organization. We used an electrostatic model of the QE field with reasonable assumptions on the location and magnitude of the cloud charge center, constrained by ELF evaluation of the Charge Moment Change in the parent flash, to show that the observed diameter of the columnar arrangement closely matches the conventional breakdown field line contour at the same altitude.