On the interception of lightning flashes by power transmission lines

The design of the lightning protection system LPS of transmission lines is based on the well known electro-geometrical model. The electro-geometrical model assumes that the first point on a power transmission line that will come within striking distance of the tip of a down-coming stepped leader channel is the strike point of the lightning flash. The model neglects almost all of the physics associated with the lightning attachment.Nowadays, as it is possible to use modern hardware and software tools and several different numerical methods, it is feasible to apply the physics of the discharge process to the study of lightning attachment. Such models take into account the movement of the downward and the resulting upward leaders from different points on the structures under consideration.In this paper, a procedure based on lightning physics was used to analyze the lightning attachment phenomena in EHV transmission lines of 230 kV and 500 kV and the results were compared with the predictions of the electro-geometrical method.     

Recent progress and new challenges in isospin physics with heavy-ion reactions

The ultimate goal of studying isospin physics via heavy-ion reactions with neutron-rich, stable and/or radioactive nuclei is to explore the isospin dependence of in-medium nuclear effective interactions and the equation of state of neutron-rich nuclear matter, particularly the isospin-dependent term in the equation of state, i.e., the density dependence of the symmetry energy. Because of its great importance for understanding many phenomena in both nuclear physics and astrophysics, the study of the density dependence of the nuclear symmetry energy has been the main focus of the intermediate-energy heavy-ion physics community during the last decade, and significant progress has been achieved both experimentally and theoretically. In particular, a number of phenomena or observables have been identified as sensitive probes to the density dependence of nuclear symmetry energy. Experimental studies have confirmed some of these interesting isospin-dependent effects and allowed us to constrain relatively stringently the symmetry energy at sub-saturation densities. The impact of this constrained density dependence of the symmetry energy on the properties of neutron stars have also been studied, and they were found to be very useful for the astrophysical community. With new opportunities provided by the various radioactive beam facilities being constructed around the world, the study of isospin physics is expected to remain one of the forefront research areas in nuclear physics. In this report, we review the major progress achieved during the last decade in isospin physics with heavy ion reactions and discuss future challenges to the most important issues in this field.     

Transcranial stimulability of phosphenes by long lightning electromagnetic pulses

The electromagnetic pulses of rare long (order of seconds) repetitive lightning discharges near strike point (order of 100 m) are analyzed and compared to magnetic fields applied in standard clinical transcranial magnetic stimulation (TMS) practice. It is shown that the time-varying lightning magnetic fields and locally induced electric fields are in the same order of magnitude and frequency as those established in TMS experiments to study stimulated perception phenomena, like magnetophosphenes. Lightning electromagnetic pulse induced transcranial magnetic stimulation of phosphenes in the visual cortex is concluded to be a plausible interpretation of a large class of reports on luminous perceptions during thunderstorms.     

From an electron avalanche to the lightning discharge

The goal of this work is to describe qualitatively the physics of processes which begin with an electron avalanche and finish in a lightning discharge. A streamer model is considered that is based on studies of the recently discovered processes occurring in the prestreamer region. The investigation and analysis of these processes enabled making the conclusion that they are, in essence, the attendant processes, which ensure the electron avalanche-to-streamer transition, and may be interpreted as a manifestation of properties of a double charge layer exposed to the external electric field. The pressing problems of physical processes which form a lightning discharge are considered from the standpoint of new ideas about the mechanism of the streamer formation and growth. Causes of the emergence of coherent super-high-frequency radiation of a leader and the neutron production in a lightning discharge are revealed that have not been explained so far in the theory of gas discharge. Based also on new ideas about the lightning discharge, a simple ball-lightning model, providing answers to almost allquestions formulated from numerous observations on the behavior of ball lightning, is offered, and the need of a new design of lightning protection instead of the traditional rod is discussed.     

On the possibility of phosphenes being generated by the energetic radiation from lightning flashes and thunderstorms

After the first report of this phenomenon by Apollo 11 astronauts, experiments conducted in space and on the ground confirmed the creation of phosphenes by the interaction of energetic radiation with the human visual system. The aim of this Letter is to show that the energetic radiation generated in the form of X-rays, gamma rays, electrons and neutrons by thunderstorms and lightning is strong enough for the creation of phosphenes in humans. It is also pointed out that some of the visual observations reported during thunderstorms might be attributable to phosphenes excited by this energetic radiation.     

Quantum Physics with Neutrons: From Spinor Symmetry to Kochen-Specker Phenomena

In 1974 perfect crystal interferometry has been developed and immediately afterwards the 4π-symmetry of spinor wave-functions has been verified. The new method opened a new access to the observation of intrinsic quantum phenomena. Spin-superposition, quantum state reconstruction and quantum beat effects are examples of such investigations. In this connection efforts have been made to separate and measure various dynamical and geometrical phases. Non-cyclic and non-adiabatic topological phases have been identified and their stability against various fluctuations and dissipative forces has been investigated by means of ultra-cold neutrons. An entanglement between different degrees of freedom of a single neutron system demonstrated the contextuality feature of quantum mechanics. In its continuation this yields to Kochen-Specker theorem like investigations providing a new basis for information processing and for the understanding of quantum physics in general. All investigations show the equivalence of various phase spaces and show how physical phenomena are correlated by quantum laws. Some curiosa occurred during the experiments and some epistemological aspects will be discussed as well.     

Charm physics — A field full of challenges and opportunities

In this review, we discuss some interesting issues in charm physics, which is full of puzzles and challenges. So far in this field, there exist many problems which have not obtained satisfactory answers yet as more unexpected phenomena Continue to be observed at the current facilities of high energy physics. Charm physics may become an ideal place for searching new resonances and studying non-perturbative QCD effects, moreover it is probably an area for exploring new physics beyond the Standard Model. More data will be available at the BE-SIII, B-factories, LHC and even the future ILC, which may open a wide window to a better understanding of its nature.      

闪电的人工触发和研究

介绍了人工引发闪电技术的发展历史和原理,以及近几年来我们利用这一技术在闪电物理研究方面取得进展。给出了人工引发闪电民流和高速摄像同步测量结果,并分析了各电流分量及其涉及的物理过程。在对比人工引发闪电与自然闪电异同的基础上,批出它的各方面都与从高建筑物始发的上行雷电十分相似。人工引发闪电在研究雷击机理、雷击效应、雷电防护以及电波传播、植物诱变育种等方面也具有广泛的应用前景。     

The role of cosmic rays in the Earth’s atmospheric processes

In this paper, we have provided an overview of cosmic ray effects on terrestrial processes such as electrical properties, global electric circuit, lightning, cloud formation, cloud coverage, atmospheric temperature, space weather phenomena, climate, etc. It is suggested that cosmic rays control short-term and long-term variations in climate. There are many basic phenomena which need further study and require new and long-term data set. Some of these have been pointed out.     

‘The mesh method’ in lightning protection standards – Revisited

At present the design of the Lightning protection systems (LPS) for structures as stipulated in standards is based on the electro – geometrical method, which was initially used to protect power lines from lightning. A derivative of the electro-geometrical method is the rolling sphere method. This method together, with the protection angle method and mesh method are used almost in all lightning standards as the measure in installing the lightning protection systems of grounded structures. In the mesh method, the dimension of the cell size in different levels of protection is determined using the rolling sphere method. Since the rolling sphere method does not take into account the physics of the lightning attachment process there is a need to evaluate the validity of the stipulated value in standards of the minimum lightning current that can penetrate through the mesh in different levels of protection. In this paper, meshes of different sizes as stipulated in the lightning protection standards were tested for their ability to intercept lightning flashes using a lightning attachment model that takes into account the physics of connecting leaders on. The results are in reasonable agreement with the specifications given in the lightning protection standards.     

Gravitational collapse and naked singularities

Gravitational collapse is one of the most striking phenomena in gravitational physics. The cosmic censorship conjecture has provided strong motivation for research in this field. In the absence of a general proof for censorship, many examples have been proposed, in which naked singularity is the outcome of gravitational collapse. Recent developments have revealed that there are examples of naked singularity formation in the collapse of physically reasonable matter fields, although the stability of these examples is still uncertain. We propose the concept of ‘effective naked singularities’, which will be quite helpful because general relativity has limitation in its application at the high-energy end. The appearance of naked singularities is not detestable but can open a window for the new physics of strongly curved space-times.     

Development of lightning rod for lightning protection standard in Europe,especially in Czech lands

This article presents a precise evaluation of the technological and social significance of the first European lightning rod, constructed in the Czech lands by the priest Václav Prokop Divi? at P?ímětice in Moravia on June 15, 1754. Discussions on the protection against lightning are known to have a rich tradition in the Czech lands (in the Habsburg monarchy) as well as in Europe as a whole. Especially the Czech lands, when compared with other countries, ranked among the leaders in terms of installed lightning rods. As for its overall impact, Divi?'s lightning rod had a significant international overlap; it proved to be of great importance even beyond the borders of the then Habsburg monarchy.The article offers not only a comparison of the efficiency and size of the protective zone of the first lightning rod by means of a computer model and contemporary mathematical and computing methods (method of the rolling sphere and the apex angle method), but it also highlights the unique social milieu in which Divi? developed his initial idea. It was an interplay of dogmatic religious scholastics and rational enlightenment in physics and natural sciences that was eventually conducive to the construction of one of the first devices for the protection against direct lightning impact. In their article, the authors also examine the transfer of knowledge on the protection against lightning impact from and to the Czech lands. A key approach to the protection against lightning was correct understanding and assessment of lightning charge, an analysis of the contact tip phenomenon and many issues relating to electrostatic phenomena. Seen in a historical perspective, the Czech lands had established an efficient platform of scientific centres, which linked up to and developed the pioneering work of Prokop Divi? several decades later. Viewed in a historical time scale, the Czech lands were represented in the branch of lightning protection primarily by Karel Václav Emanuel Zenger, Franti?ek Běhounek, Josef Postránecký, Ladislav V. ?íhánek, Franti?ek Popolanský and many others.Also in terms of standardization, the Czech Republic has been active on a long-term basis, while espousing the European standards with its own ?SN EN 62 305 standard. In many other respects, this country has been loyal to traditions; after all, the very first decree on the protection of gunpowder depots against lightning in the Habsburg monarchy came from Empress Maria Theresa and was published shortly after 1778. The lightning protection standard, issued by the Czechoslovak Electrical Engineering Union in the 1950s, had introduced a fundamentally new concept that served for the implementation of most protective systems in this branch until 2006.     

The warm inflationary universe

In the past decade, the importance of dissipation and fluctuation to inflationary dynamics has been realized and has led to a new picture of inflation called warm inflation. Although these phenomena are common to condensed matter systems, for inflation models their importance has only recently started to be appreciated. The article describes the motivation for these phenomena during inflation and then examines their origins from first principles quantum field theory treatments of inflation models. Cosmology today is a data intensive field and this is driving theory to greater precision and predictability. This opens the possibility to consider tests for detecting observational signatures of dissipative processes, which will be discussed. In addition, it will be discussed how particle physics and cosmology are now working in tandem to push the boundaries of our knowledge about fundamental physics.     

Transport phenomena in spin caloritronics

The interconversion between spin, charge, and heat currents is being actively studied from the viewpoints of both fundamental physics and thermoelectric applications in the field of spin caloritronics. This field is a branch of spintronics, which has developed rapidly since the discovery of the thermo-spin conversion phenomenon called the spin Seebeck effect. In spin caloritronics, various thermo-spin conversion phenomena and principles have subsequently been discovered and magneto-thermoelectric effects, thermoelectric effects unique to magnetic materials, have received renewed attention with the advances in physical understanding and thermal/thermoelectric measurement techniques. However, the existence of various thermo-spin and magneto-thermoelectric conversion phenomena with similar names may confuse non-specialists. Thus, in this Review, the basic behaviors, spin-charge-heat current conversion symmetries, and functionalities of spin-caloritronic phenomena are summarized, which will help new entrants to learn fundamental physics, materials science, and application studies in spin caloritronics.     

Estimation of charge neutralized by negative cloud-to-ground flashes in Catalonia thunderstorms

Charges neutralized by lightning flashes have been usually located and inferred from the quasi-static changes in the vertical component of electric field (ΔE) obtained from multiple synchronized measurement stations. In this paper, the charges neutralized by negative cloud-to-ground (?CG) lightning flashes are located and inferred using single station electric field measurements in combination with total lightning (cloud-to-ground and intra-cloud) data from lightning detection networks in the north-eastern region of Spain. The altitude of the negative charge region in 8 thunderstorms examined here was in the range of 5.8–7.2 km as inferred from temperature soundings. Charge locations are assumed to be in the region where the VHF (Very High Frequency) sources associated with the discharge are located. The quantity of charge neutralized is calculated using a point charge model and the measured vertical component of electric field (ΔE) associated with each flash. The results are compared with those previously obtained from measurements carried out in the NASA Kennedy Space Center (KSC) in Florida. The analysis of 260 ?CG flashes from eight thunderstorms reveals a median charge value of ?9.7 C with 95% of the values ranging between ?4.5 C and ?45 C.     

Amplitudes for astrophysicists: known knowns

The use of quantum field theory to understand astrophysical phenomena is not new. However, for the most part, the methods used are those that have been developed decades ago. The intervening years have seen some remarkable developments in computational quantum field theoretic tools. In particle physics, this technology has facilitated calculations that, even ten years ago would have seemed laughably difficult. It is remarkable, then, that most of these new techniques have remained firmly within the domain of high energy physics. We would like to change this. As alluded to in the title, this paper is aimed at showcasing the use of modern on-shell methods in the context of astrophysics and cosmology. In this article, we use the old problem of the bending of light by a compact object as an anchor to pedagogically develop these new computational tools. Once developed, we then illustrate their power and utility with an application to the scattering of gravitational waves.     

Detection of high-energy gamma rays from winter thunderclouds

A report is made on a comprehensive observation of a burstlike gamma-ray emission from thunderclouds on the Sea of Japan, during strong thunderstorms on 6 January 2007. The detected emission, lasting for approximately 40 sec, preceded cloud-to-ground lightning discharges. The burst spectrum, extending to 10 MeV, can be interpreted as consisting of bremsstrahlung photons originating from relativistic electrons. This ground-based observation provides the first clear evidence that strong electric fields in thunderclouds can continuously accelerate electrons beyond 10 MeV prior to lightning discharges.     

Lightning effects at high altitudes: sprites, elves, and terrestrial gamma ray flashes

A fascinating set of newly discovered complex phenomena indicate that thunderstorms and lightning discharges are strongly coupled to the overlying upper atmospheric regions. Lightning discharges at cloud altitudes (<20 km) affect altitudes >40 km either via the release of intense electromagnetic pulses (EMPs) and/or the production of intense quasi-static electric (QE) fields. The intense transient QE fields of up to 1 kV·m⁻¹, which for positive CG discharges is directed downwards, can avalanche accelerate upward-driven runaway MeV electron beams, producing brief (1 ms) flashes of gamma radiation. A spectacular manifestation of these intense fields is the so-called ‘Sprites’, large luminous discharges in the altitude range of 40 km to 90 km, which are produced by the heating of ambient electrons for a few to tens of milliseconds following intense lightning flashes. The so-called ‘Elves’ are optical flashes which last much shorter (<1 ms) than sprites, and are typically limited to 80–95 km altitudes with much larger (up to 600 km) lateral extent, being produced by the heating, ionization, and optical emissions due to the EMPs radiated by both positive and negative lightning discharges. To cite this article: U.S. Inan, C. R. Physique 3 (2002) 1411–1421.     

Topical issue on Geometry, Integrability and Nonlinearity in Condensed Matter Physics

Recent developments in the study of nonlinear phenomena have led to the realization that a combination of the concepts of integrability, geometry and topology provides a new powerful framework for describing a great variety of physical systems. It was therefore felt that the compilation of a special issue comprising articles on the interdiseiplinary topic of Geometry, Integrability and Nonlinearity in Condensed Matter Physics, would indeed be timely. The enthusiastic response and support that we received from the active researchers in this subject, when we organized an International Conference on the above topic from July 15 to July 20, 2001, in Bansko, Bulgaria, provided a further motivation for undertaking this task. As the topic is interdisciplinary in nature, the articles in this volume contain new results on a wide range of subjects. These include among others, integrable equations and the interplay between geometry and nonlinearity, the role of optical solitons in communication. (and, possibly, computation), common nonlinear and geometrical aspects of condensed matter, field theory, and so on. The increasingly important role played by geometry and topology in diverse areas such as the quantum Hall effect, localization, deformation and elasticity, quasiparticle kinetics and dynamics, spin systems, membranes, is highlighted in some of the articles. There are papers in which essential links of nonlinearity to differential geometry are identified and many elegant mathematical methods are presented. Some other articles focus on how the mathematical tools of geometry and nonlinear analysis can be applied to solve certain physical problems. Given the vast range of titles, it was difficult to strictly divide the contributions into distinct categories. Except for the pedagogical introductory article by Rajaraman titled "CP _N Solitons in Quantum Hall Systems", which essentially "sets the stage" for the various themes covered, we have grouped the articles broadly under the following headings: Geometry, integrability and mathematical physics; Solitons: Interaction phenomena, nonlinear optics; Condensed matter physics; Soft condensed matter physics; Quantum phenomena. We gratefully acknowledge the support from Los Alamos National Lab, USA; Université de Cergy-Pontoise, France; The Abdus Salam International Centre for Theoretical Physics, Trieste, Italy and the Institute for Nuclear Research and Nuclear Energy, Sofia, Bulgaria, in putting this special volume together. We believe that the cross-fertilization and synergy of a host of ideas in seemingly disparate fields of physics would lead to the natural emergence of new paradigms, which in turn could pave the way for collaborative research to arrive at new solutions of complex nonlinear problems. It is our hope that this topical issue will be useful in providing an impetus for achieving this broad objective. Radha Balakrishnan, Chennai, India Rossen Dandoloff, Cergy-Pontoise, France Vladimir Gerdjikov, Sofia, Bulgaria Dimitar Pushkarov, Sofia, Bulgaria Avadh Saxena, Los Alamos, USA