La ligne bleue survolee - Special CNEGU - 1991

Magazine Overview

Title: LA LIGNE BLEUE SURVOLEE ?
Issue: Spécial
Date: 1991
Publisher: CERCLE VOSGIEN LUMIERES DANS LA NUIT
Country: France
ISSN: 0293-2032

This special issue of "La Ligne Bleue Survolée ?" is the bulletin of the "Cercle Vosgien LDLN," a delegation from the Vosges region and a member of the "Comité Nord-Est des Groupements ufologiques" (CNEGU). The bulletin's address is 6, Avenue Salvador Allende, Centre d'Activités Léo Lagrange, 88000 EPINAL.

Editorial Stance and Content Overview

The editorial, penned by Gilles MUNSCH, reflects on the year's end and the 40th session of CNEGU. It highlights the longevity and maturity of the CNEGU, which has been active for 12 years, and wishes it continued success. The editorial notes a recent "agitation" in the news, particularly concerning the "Crop Circles" phenomenon, suggesting that the solution might involve intelligent, human-made fabrications rather than extraterrestrial origins. It cautions against accepting claims of authorship from two elderly Englishmen without verification. The editorial also revisits the "Ummites" case, mentioning Jean-Pierre PETIT and Martine CASTELLOS, and calls for an open yet prudent attitude towards these claims. Furthermore, it points to new cases reported in the Nord-Est region that are described as strange and recurrent, awaiting further information. The editorial concludes by emphasizing the bulletin's role as a tribune for CNEGU, encouraging readers to express themselves freely.

Key Articles and Features

Sommaire Numero Special 40eme CNEGU

• The issue includes a table of contents for this special number, featuring:
• EDITORIAL: By Gilles MUNSCH.
• LA FORET DE DARNEY (SUITE): By CVLDLN (Francine JUNCOSA) with the help of Raoul ROBE.
• DISCUSSION DES CINQ ARGUMENTS ANTI HET DE J. VALLEE: Article by Eric MAILLOT and a supputation by Raoul ROBE.
• LE RETOUR DE L'HET: By Raoul ROBE.
• OBSERVATION OU VISION AU-DESSUS DE PARIS: By Raoul ROBE.
• COMMUNICATIONS SUR CAS D'OVNI ALLEGUES: By Robert FISCHER.
• EXPOSE SUR LA FOUDRE (CNEGU DE JUIN 91): By Robert FISCHER.

An important announcement states that the CVLDLN will soon publish a new volume compiling press articles about UFOs from "La Liberté de l'Est" newspaper between 1964 and 1969. Inquiries should be directed to Isabelle DUMAS.

La Forêt de Darney - Suite

This section continues the discussion from a previous issue regarding an article about "La Ligne Bleue Survolée ?" and its relation to "logie physique." It includes excerpts from Frédérique Hébrard's "La Dragonnade," which recounts a childhood experience involving dragons, biblical invocations, and a vision of a "visionary" child. The narrative describes a surreal journey through a magical landscape, encountering elements like talking animals and a mysterious portal. The child's experience is presented as a profound "experience" that she will carry with her, even as she faces disbelief from adults.

Contre-Enquête - Darney (88) - Juillet 1974

This article details a "counter-investigation" into a UFO observation that occurred in late July 1974 near the Darney train station. The information was initially provided by GPUN in 1976 and later included in Michel Fiquet's "Premier dossier des rencontres rapprochées en France." The investigation adds details to the initial report, noting that no physical traces were found at the scene. Witnesses described an ovoide-shaped object, approximately 2.50 meters high, behind a strong luminescence. The witnesses are described as credible and known for their honesty, having chosen to remain anonymous. The investigation involved topographical surveys to determine the observation's azimuth, estimated to be between 242 and 248 degrees magnetic, or approximately 245 degrees geographic (West-South-West of the witnesses). The article also notes changes to the location, such as the disappearance of the railway line and the conversion of the station into a private residence.

Sophrology and UFOs

Francine JUNCOSA contributes a section discussing the similarities between a reported "experience" by a young girl in the forest of Darney and the narrative of Frédérique Hébrard. She notes that when people describe pleasant environments, they often depict pastoral settings with harmonious natural elements. JUNCOSA suggests that through sophrology exercises, individuals can experience these environments vividly, associating them with familiar sounds and smells. She draws a parallel between sophrology and hypnosis, noting the existence of auto-hypnosis.

Recurring Themes and Editorial Stance

The recurring themes in this issue include UFO sightings, investigations into specific cases (like Darney), and the analysis of phenomena such as "Crop Circles." The editorial stance, as expressed by Gilles MUNSCH, is one of cautious inquiry, encouraging critical thinking and verification of claims, while also acknowledging the ongoing interest and importance of ufological research. The bulletin positions itself as a vital platform for the CNEGU, fostering open discussion and the sharing of information within the ufological community in France and beyond.

This document, identified as F/15/88740700 (01) DARNEY (88), is a French publication from July 1974. It appears to be a specialized report or magazine issue focusing on a specific UFO (OVNI) case in Darney, France. The content includes detailed analysis, witness accounts, astronomical data, and a critical review of existing theories.

Analysis of the Darney UFO Sighting (July 24-25, 1974)

The core of the issue revolves around an alleged UFO sighting that occurred around July 24th and 25th, 1974, in Darney. The authors, Francine Juncosa and Gilles Munsch, present a thorough investigation that leans heavily towards explaining the phenomenon as a misidentification of the moon.

Astronomical Calculations and Witness Testimony

The analysis meticulously compares the reported sighting times and directions with the position of the moon. Astronomical calculations, performed using a micro-computer with the "astro" software, are presented for July 24th and 25th, 1974. These calculations show the moon's azimuth and angular height at various times, demonstrating that it was indeed close to the horizon and in the observed azimuth during the reported sighting times. The authors note that the witnesses' reported time might have been off by about half an hour, which would still place the moon in a relevant position.

They argue that the possibility of mistaking the moon for a UFO is significant, especially given its proximity to the horizon and the potential for atmospheric refraction to distort its appearance. The report also considers the possibility of confusion with planets but dismisses it as improbable given the descriptions.

Rejection of Extraterrestrial Hypothesis

The authors critically examine the evidence and conclude that the extraterrestrial hypothesis is unlikely. They suggest that the phenomenon described is most likely the moon, and that the witnesses, while likely sincere, may have been mistaken. The report highlights the difficulty of finding a natural or artificial phenomenon that could explain the observation, but finds the moon to be the most plausible explanation.

Supporting Evidence and Context

To further contextualize the report, the issue includes a list of press articles from "La Liberté de l'Est" (Quotidien des Vosges) for 1974, detailing various UFO sightings reported in France during that year. This demonstrates that UFOs were a topic of public interest at the time. Additionally, a cartoon by "Dr. Maillot" humorously suggests that in any UFO investigation, one should "Look for the Moon!" This reinforces the central theme of the analysis.

Discussion of Jacques Vallée's Arguments

The document also features a section discussing the arguments of Jacques Vallée against the extraterrestrial hypothesis (H.E.T.). The authors summarize Vallée's points, including the high percentage of UFO sightings that are likely misidentifications (38% possible UFOs, 62% misidentifications, according to French GEPAN/SEPRA data). They also reference data from the Colorado report (USA) which indicates a much lower percentage of actual UFOs (6%) compared to misidentifications (94%). The authors find Vallée's arguments compelling, particularly his assertion that most UFO reports can be explained by psychological or socio-psychological interactions with the environment, rather than extraterrestrial craft.

Conclusion

The issue concludes that the Darney sighting is highly likely a case of misidentification of the moon. The authors emphasize the need for further interviews with the witnesses to definitively confirm or refute their hypothesis. They express that, for now, the evidence points towards the witnesses and investigators being "somewhat in the moon" themselves, in a figurative sense.

Recurring Themes and Editorial Stance

The recurring themes in this issue are the analysis of UFO sightings, the importance of astronomical knowledge in identifying aerial phenomena, and the critical examination of the extraterrestrial hypothesis. The editorial stance is clearly skeptical of the extraterrestrial explanation for the Darney case, favoring a rational, scientific explanation based on misidentification, primarily with the moon. The publication advocates for rigorous investigation and data-driven conclusions, even when dealing with potentially sensitive or sensational topics.

This issue of "Confrontations", identified as issue number 40 and dated July 10, 1991, is published by SERPAN and focuses on a debate concerning ufology, particularly the arguments presented by Jacques Vallée. The cover headline is 'CONFRONTATIONS D'UNE AUTRE DIMENSION', and the main visual is a cartoon satirizing the debate.

Article 1: Confrontations d'une autre dimension (Pages 9-10)

This section presents a correspondence between Eric Maillot and Jacques Vallée. Maillot criticizes Vallée's article, accusing him of personal attacks and bad faith. Vallée responds by stating he does not intend to answer an article that he considers to be a series of personal attacks unrelated to the scientific debate. He accuses Maillot of insinuating he is dishonest and of misrepresenting his statements.

Maillot then offers his own remarks on Vallée's arguments:

1. Personal Attacks: Maillot admits his initial version was incisive but not insulting, while Vallée's response was a prospectus for his OVNIBASE software, which he calls 'discourteous'.
2. Dignity and Content of Scientific Debate: Maillot believes Vallée prefers to focus on the 'form' rather than the 'content' of the arguments, potentially due to personal affect rather than intellectual engagement. He questions if Vallée has anything to respond to intellectually.

Maillot concludes that for a scientific debate to occur, one must at least acknowledge the facts, formulate a hypothesis, select samples, and verify the hypothesis through comparative tests. He references Vallée's work published in the 'Journal of scientific exploration' and suggests that Vallée's approach remains at the stage of observation and sampling, not scientific verification.

Maillot labels Vallée's stance as 'Mauvaise foi anti-scientifique' (Anti-scientific bad faith), stating he has self-censored his article to remove polemical or corrosive passages to preserve only the arguments. He intends to submit this revised text for publication.

Article 2: II - SON DEUXIEME ARGUMENT: Les entités associées aux ovnis sont trop humanoïdes (Pages 1-2)

This section, part of a larger critique of the HET (Humanoid Extraterrestrial) theory, argues that alleged alien entities often appear too human-like. The author notes that these entities frequently wear gloves, glasses, boots, and military-style suits, and possess human-like limbs. The experience of Antonio Villa Boas, who claimed sexual relations with such entities, is cited as an example. The author questions the realism of these descriptions, referencing the 'Hopkinsville green little man' and suggesting that if these beings are not from another planet, they might originate from a parallel dimension or another time.

Article 3: III - SON TROISIEME ARGUMENT: Les récits d'abductés sont trop barbares (Pages 3)

This part of the critique focuses on abduction accounts, describing them as particularly traumatic and characterized by 'missing time' (amnésie). These accounts, often involving medical or sexual procedures, are said to be proliferating, particularly in the American context. The author questions why advanced extraterrestrial intelligences would operate with such lack of discretion, causing trauma to their subjects, comparing it to medical experiments on humans or animals.

Article 4: IV - SON QUATRIEME ARGUMENT: Un phénomène historiquement trop ancien, trop proche de notre technologie, trop proche de notre culture (Pages 3-4)

This argument posits that the UFO phenomenon is too ancient and deeply rooted in human culture and folklore to be of extraterrestrial origin. The author suggests that UFOs are not a new phenomenon but rather an anticipation of human technological and cultural evolution. The article mentions historical examples like dirigibles and early aircraft, implying that UFO sightings often reflect contemporary human technological advancements and anxieties.

Article 5: V - SON CINQUIEME ARGUMENT: Un phénomène à composante trop physique et défiant trop la physique (Page 4)

This argument contrasts the technological, 'machine-like' aspect of UFOs with their ability to defy known physics, such as appearing and disappearing suddenly or changing shape. The author suggests that these capabilities might be explained by mastery of space-time or travel through 'other dimensions,' a concept explored in Vallée's trilogy.

Article 6: Analysis of UFO Data and Explanations (Pages 5-7)

This section delves into the statistical analysis of UFO data, particularly referencing the work of Jacques Vallée and organizations like GEPAN/CNES. The author discusses the limitations of available data, the difficulty in verifying witness accounts, and the potential for misinterpretations and biases. The article highlights that many UFO sightings can be explained by misidentifications, such as mistaking the moon for a UFO. It emphasizes the 'human dimension' of the phenomenon, suggesting that perception, communication biases, and psychological factors play a significant role in shaping UFO reports.

The author critiques the methodology of some UFO researchers, including Vallée, for what he perceives as a tendency to dismiss evidence that doesn't fit pre-conceived notions, particularly those favoring socio-psychological explanations. The article concludes by questioning the scientific rigor of some UFO research and suggesting that a critical re-evaluation is needed.

Notes and References (Pages 6-7)

The issue includes several notes and references that support the arguments presented. These include citations to works by Denys Breysse, GEPAN/CNES technical notes, and articles from various ufological publications. Note (5) specifically warns against the superposition of data and encourages caution when interpreting statistics, particularly concerning the percentage of probes sent to Mars.

Recurring Themes and Editorial Stance

The recurring themes in this issue revolve around the debate between scientific rigor and speculative theories in ufology. The editorial stance, as represented by Eric Maillot, is critical of approaches that dismiss potential extraterrestrial origins too readily, particularly Vallée's socio-psychological explanations. There is a strong emphasis on the need for verifiable evidence and a critical examination of witness testimony and statistical data. The issue champions a more open-minded yet scientifically grounded approach to understanding UFO phenomena, while also acknowledging the role of human perception and cultural context.

Title: LE RETOUR DE L'HET (The Return of the HET)

Subtitle: Hypothèse extraterrestre (Extraterrestrial Hypothesis)

Issue Date: June 1991

Publisher: La Ligne Bleue Survolée

Country of Publication: France

Language: French

Document Type: Magazine Issue

Content Summary

This issue of "LE RETOUR DE L'HET" focuses on the renewed interest in the Extraterrestrial Hypothesis (HET), spurred by recent book publications and film releases. The cover prominently features the title and a graphic illustration of a UFO, with the subtitle "Hypothèse extraterrestre."

Articles and Features

The magazine opens with a discussion of how the HET, which had seen a decline in interest, is being revitalized by new media. It mentions three books: "Ces ovni qui font peur" by Jean SIDER and Axis Mundi, "Enquête sur des extraterrestres" by Jean-Pierre PETIT, and "Le mystère des Ummites" by Albin Michel. The release of two films, "UN DIEU REBELLE" (directed by Peter Fleischmann) and "SIMPLE MORTEL" (directed by Pierre JOLIVET), are also highlighted. These films explore the idea of Earth as a zoo for extraterrestrial intelligences, a theme previously touched upon by Jean-Christophe AVERTY.

"UN DIEU REBELLE" is described as a film about a primitive planet observed by extraterrestrial "incognitos" who are eventually discovered and "retrieved" by their superiors, revealing that the observers themselves were part of a sociological experiment. "Le dernier combat" by Pierre JOLIVET is presented as a more suspenseful psychological thriller where a linguist receives mysterious radio messages.

Jacques VALLEE's skepticism towards the HET is noted, with the article suggesting that serious arguments for extraterrestrial intelligence might emerge from fields like astronomy (discovery of exoplanets) and theoretical physics, posing the question of whether the "Hubble" telescope could shed light on this.

UFO Sightings and Cases

A significant portion of the magazine is dedicated to UFO reports. Raoul ROBE contributes an account of an observation in Paris on March 1, 1991. While commuting on an elevated metro line, he witnessed a large, grey, metallic mass hovering near the dome of the Invalides. The object was described as oval with rounded and tubular protuberances, perfectly immobile, with sharp contours, and no audible noise. Despite checking with air traffic control and the tourist office, no conventional explanation was found. Hypotheses considered included reflections in the train window or a cloud, but these were deemed unlikely.

Robert FISCHER provides a compilation of UFO sightings from November 1990 to April 1991, primarily in France. These include:

• December 14, 1990: A couple in Moyenvic (57) saw a metallic disc moving towards Nancy.
• December 16, 1990: An oval object over Nancy "exploded" into sparks.
• December 24, 1990: A green fireball was seen near Chateau Salins, ascending vertically.
• December 25, 1990: Another green fireball was observed near Chateau Salins.
• December 30, 1990: An orange disc was seen near Toul.
• January 2, 1991: A silent object was observed in the Haye forest.
• January 5, 1991: A large triangular object hovered for several minutes near Colombey les Belles.
• January 16, 1991: A triangular object was observed in the Baccarat region.
• January 21, 1991: A white, egg-shaped object was seen near Autreville.
• February 1, 1991: A dark, oval object flew over the suburbs of Nancy, illuminating with a green hue.
• February 2, 1991: Three groups of witnesses in Metz observed a rectangular object flying low.
• February 9, 1991: Three silver discs in formation were seen near Saint Avold (57).
• February 9, 1991: Two fireballs were seen near Morhange (57).
• February 14, 1991: A silver ball was observed near the Vosges and Meurthe/Moselle border.
• February 19, 1991: Four observations were made, including a couple seeing an orange disc near Lunéville, two youths seeing a bright triangle near Baccarat, a group seeing two fireballs, and workers observing a blue cigar-shaped object in Sarrebourg (57).
• March 1, 1991: Three simultaneous observations of a silver disc occurred in Longwy, Blâmont, and Toul.
• March 9, 1991: A disc was encountered at close range in the Haye forest.
• March 22, 1991: Three people reported being pursued by a fireball near Laitre sous Amance.
• March 23, 1991: Two fireballs were seen pursuing a car in Custines.
• April 1, 1991: A dark triangle was observed in the Haye forest, disappearing without a trace.

Fischer notes that these observations are presented without conventional explanations and that further, stranger cases are emerging.

Lightning and Electromagnetic Phenomena

The magazine also includes an article by Robert FISCHER discussing lightning. It highlights the frequency of lightning strikes globally and in France, the resulting damage (victims, fires, destruction of property and infrastructure), and existing protection measures like lightning rods and surge suppressors. The article draws a parallel between the rapid electrical currents and intense magnetic radiation from lightning strikes and potential indirect effects observed in some UFO phenomena, suggesting that these electromagnetic induction phenomena could affect electrical and telephonic installations.

Recurring Themes and Editorial Stance

The primary theme of this issue is the resurgence of the Extraterrestrial Hypothesis (HET) and the ongoing investigation into UFO phenomena. The editorial stance appears to be one of open inquiry, presenting various sightings and theoretical possibilities without outright dismissal. The magazine encourages readers to consider unconventional explanations and highlights the need for continued data collection and analysis. The inclusion of a detailed personal sighting report and a compilation of numerous cases suggests a focus on empirical evidence and witness testimony. The discussion of lightning and its electromagnetic effects hints at an exploration of potential physical mechanisms that could be related to UFO phenomena, moving beyond purely speculative origins.

This issue of 'Revue d'Informations' (Issue 3) focuses on the critical interplay between lightning and electromagnetic phenomena, exploring its implications for modern technology and the underlying physics of thunderstorms. The cover prominently features the headline 'La Foudre et les Phénomènes Électromagnétiques' (Lightning and Electromagnetic Phenomena).

Electromagnetic Induction and Electronic Systems

The article begins by highlighting the crucial role of electromagnetic induction in the era of semiconductors, where low energy levels make systems vulnerable. It explains that induced overvoltages can lead to malfunctions or the destruction of electronic components. This risk is particularly relevant for systems connected by wiring, including remote controls, computers, and telephone switching circuits.

Challenges in Aviation and Future Aircraft

Aircraft manufacturers are paying close attention to these phenomena. To reduce the weight of future aircraft and improve their mechanical resistance, synthetic materials based on resins will be increasingly used. However, these materials are poor electrical conductors and transparent to electromagnetic radiation, offering minimal protection. Furthermore, future aircraft will rely on electrically controlled systems managed by onboard computers, necessitating components that are highly reliable and insensitive to electromagnetic disturbances.

Understanding Thunderstorms and Lightning

The publication emphasizes the necessity of understanding lightning as a danger. Research is directed towards understanding the physics of storm clouds, the distribution and severity of storms, how lightning strikes, and its magnetic radiation.

Physical Characteristics of Storm Clouds

Thunderstorm clouds, typically cumulonimbus formations resembling anvils, are massive structures spanning tens of kilometers and reaching altitudes of around 2,000 meters. They contain thousands of cubic kilometers of water and weigh hundreds of thousands of tons. Their formation is driven by updrafts with speeds of approximately 20 m/s.

Types of Storms

Convection storms, or isolated storms, originate from the combination of humidity and local ground heating, forming a bubble of warm, humid air that rises. These are often localized and short-lived, lasting about an hour and a half. Frontal storms, on the other hand, arise from the meeting of air masses with different temperatures and humidity levels, leading to updrafts and condensation. These can cover vast areas and last for many hours.

Theories of Charge Separation

Within these clouds, electrical charges separate. Several theories attempt to explain this process, dating back to Lénard's work in 1892. While no single theory is sufficient, likely multiple simultaneous mechanisms are at play. These include:

• Collision and Ion Capture: Proposed by Professor Sartor (NCAR, Boulder) in 1970, involving collision of precipitation with selective ion capture.
• Droplet Rupture: Suggested by Mattew and Mason from the Imperial College of London in 1964.
• Phase Change Effects: Including freezing in supercooled water or thermoelectric effects in ice, proposed by Takahashi (Tokyo) in 1966.

Regardless of the specific mechanism, once charges are separated, they are carried by different particles. Lighter positive charges are carried upwards by updrafts, while heavier negative charges fall.

Cloud Electrification and Electrical Fields

The result of charge separation is that the top of the cloud becomes positively charged, and the base negatively charged. Often, an island of positive charge is embedded within the negative mass, its presence and role not fully understood. Charge values are estimated to be in the range of tens to hundreds of coulombs.

As a storm approaches, it forms a vast dipole, creating electrical fields within the cloud and between the cloud base and the ground. A weak electrical field, typically 100 to 150 V/m, is normally present near the ground due to positive charges at high altitudes (around 50 km), though its origin is unknown.

When a storm cloud forms or approaches, the negative charges at its base become dominant, causing the ground-level electric field to invert and grow significantly. When this field reaches approximately -15 to -20 kilovolts per meter, a ground discharge (lightning) becomes imminent.

The 'Point Effect' and Lightning Strikes

Ground topography significantly influences the electric field. The 'point effect' dictates that any sharp protrusion on a surface locally intensifies the electric field, particularly at its apex. This manifests as electrical effluences, often seen as blue-violet filaments extending from points. These are known as St. Elmo's Fire and are recognized by sailors and mountaineers as a sign of imminent danger.

For modest asperities like trees or church steeples, these effluences are localized. However, on larger structures like pylons or tall towers, the filaments can extend significantly, forming an ascending discharge that can reach the cloud, resulting in an 'ascending lightning strike.' Such strikes are frequently observed from television towers and skyscrapers. In flat terrain, the normal lightning strike is a 'descending lightning strike.'

Descending Lightning

The first phase of a descending lightning strike is a luminous precursor, a weakly ionized channel that propagates downwards. This 'stepped leader' moves towards the ground in successive steps of tens of meters, at speeds between 0.15 to 0.5 meters per microsecond, characterized by numerous branches.

As the stepped leader nears the ground, pre-existing St. Elmo's Fire intensifies, transforming into ascending discharges. When an ascending discharge meets the stepped leader, a conductive path is established between the cloud (at millions of volts) and the ground, allowing a high-intensity current to flow. This connection typically occurs at an altitude of about 100 meters. The stepped leader is not influenced by ground relief or terrain, meaning a lightning rod or a pointed object only attracts lightning if it is very close.

Ascending Lightning and Return Strokes

The actual lightning strike, or 'return stroke,' consists of the surface charges on the ground, induced by the cloud charges, neutralizing the charges in the leader channel as it travels upwards. This creates a luminous arc from the ground to the cloud, traveling at one-third the speed of light. A single lightning strike can involve multiple return strokes, lasting from 0.1 to 1 second, with some observed durations of up to 3 seconds, characterized by multiple re-illuminations.

Most ground lightning strikes in temperate latitudes (around 90%) are negative, originating from the negatively charged base of the cloud. However, if the discharge originates from a positive charge island, the leader moves in a straight line without steps. This channel heats intensely, resulting in a very bright return stroke, reaching temperatures of 20,000 to 30,000 K and a diameter of about 2 centimeters. The electrodynamic forces during the return stroke concentrate the channel, causing an explosive pressure increase of two to three atmospheres, which dissipates when the lightning ceases, creating a shockwave perceived as thunder.

Thunder Perception

The perception of thunder varies with the observer's position relative to the strike. The duration of the strike is related to the channel length. The sound is a result of multiple small channels and their shockwaves. High-frequency components of the shockwave propagate perpendicularly to the channel segment, while low frequencies are multidirectional. This results in a perceived sound that can be a sharp crack or a dull rumble, depending on the angle and distance to the channel.

Research and Measurement of Lightning

Beyond electromagnetic radiation, most lightning data has been collected using instruments on towers and tall structures. Examples include the observatory on the peak of San Salvatore near Lake Lugano, where a television antenna is struck multiple times annually. Researchers Berger and Zaengl from the Zurich Polytechnic installed sensors on lightning current paths at this location, as well as at stations in Varese and Foligno, Italy.

Similar instrumented towers exist near Pretoria (South Africa) and the Empire State Building, along with television towers in Munich and Toronto. These efforts have allowed for the description of various lightning parameters. For instance, return strokes of negative lightning strikes are brief impulses with an average intensity of 20 kiloamperes, while positive strikes can reach 200 kiloamperes, with one observed strike at 500 kiloamperes.

Energy Potential and Storage

While the instantaneous energy of lightning is considerable, its average power is modest. The total annual energy from lightning strikes in France is estimated to be around 100 MW, equivalent to one-tenth of a nuclear power plant's output. However, storing such a concentrated, instantaneous energy is extremely difficult.

Measuring Cloud Charges

Instrumented towers have also helped in measuring the total charge neutralized during a storm. Measuring electrostatic charges directly within clouds is challenging. One method involves deploying field probes over large areas to deduce the charge distribution within the cloud. However, this can be skewed by a layer of space charge about fifty meters thick above the ground, caused by the 'corona effect' from existing St. Elmo's Fire on asperities.

To overcome this, probes attached to small balloons are used. These high-altitude measurements indicate electric field strengths of 200 to 250 kV/m within the storm cloud. Initial results suggest that the reinforcement of the field near large hydrometeors (aerosol-like precipitation) plays a crucial role in initiating the process, though the electrification process is not yet fully understood.

Predicting Lightning Impact Points

Models, such as the electrogeometric model, are used to predict lightning impact points. This model describes the development of the descending leader channel from the cloud to the ground. The normal leader, originating from the negative part of the cloud, carries a negative charge. As it approaches the ground, the electric field below it intensifies significantly within milliseconds. When the ground-level electric field reaches about 300 kV/m, local St. Elmo's Fire transforms into ascending discharges that move towards the leader. The closest or fastest ascending discharge connects with the leader, forming a continuous channel between the cloud and the ground, allowing the main return stroke to occur.

The impact point is then fixed. To predict these points, the conditions for the development of ascending discharges need to be analyzed numerically. Based on reasonable hypotheses about charge distribution along the leader, a relationship is established between the leader-ground distance and the current intensity. This distance, known as the 'leader-ground distance' or 'striking distance,' varies from 20-30 meters for weaker currents to 250-300 meters for stronger ones. For an average current of 25 kA, this distance is about 80 meters. Therefore, the first object encountered within this striking distance is likely to be struck.

Provoking Lightning Strikes

To accelerate research, attempts have been made to artificially provoke lightning. The most successful method involves launching a rocket trailing a thin metallic wire. As the rocket approaches a storm, the rocket-wire system acts as a lightning rod, triggering a strike when it reaches an altitude of 50 to 500 meters.

Keraunic Level

Historically, the severity of storms was characterized by the 'keraunic level,' which is the number of days per year with audible thunder. While rudimentary, this is useful given that lightning can only be perceived within a 10-kilometer radius. The average in France is 10-15 days per year, with a maximum of 36. In Florida and Indonesia, this level can reach 180 days per year, and even 220 in Java.

Lightning Detection Systems

Physicists also seek indices per square kilometer, with densities calculated at 1 to 4 lightning strikes per square kilometer in some regions. To improve data, localization systems have been developed.

• LLS (USA): This system uses radiogoniometry, where flat coil frames are sensitive to the magnetic component of an electromagnetic field. Two crossed frames at 90 degrees allow detection of the direction of the electromagnetic wave. Three stations can triangulate to pinpoint the lightning impact with an accuracy of one degree, corresponding to an error of 300 meters at 20 km distance, or 3 km at 200 km distance. The LLS system is sensitive only to return strokes, allowing measurement of maximum intensity and filtering out intra-cloud lightning.
• METEORAGE (France): This system, developed in France, uses sixteen stations spaced 200 to 300 kilometers apart.
• SAFIR (ONERA, France): This system combines LLS capabilities with the detection of intra-cloud lightning. It captures radiation in the 100 MHz to 1000 MHz range emitted by lightning using an interferometric station, also employing triangulation for precise impact localization.

Recurring Themes and Editorial Stance

The recurring theme throughout this issue is the significant and often underestimated impact of lightning and electromagnetic phenomena on modern technology, particularly in critical fields like aviation. The publication adopts a scientific and investigative stance, detailing the physical processes involved, presenting various research theories and findings, and highlighting the ongoing efforts to understand and mitigate the risks associated with lightning. The emphasis is on the need for continued research and technological development to address these powerful natural forces.