Lightning Physics

Petir merupakan salah satu fenomena alam yang sangat berbahaya karena energinya yang sangat besar. Setiap kali petir menyambar bisa mengeluarkan energi hingga jutaan volt. Selain itu petir juga selalu bersinggungan dengan kehidupan manusia khususnya petir tipe Cloud to Ground (CG). Kejadian sambaran petir sering menimbulkan kerugian fisik, material bahkan tidak jarang juga menimbulkan korban jiwa.  Provinsi Sulawesi Selatan merupakan salah satu provinsi di Indonesia bagian timur yang cukup padat penduduknya. Dari latar belakang tersebut maka dilakukan penelitian mengenai analisis spasial dan temporal tingkat ancaman sambaran petir CG di wilayah Provinsi Sulawesi Selatan. Penelitian ini menggunakan data petir tipe CG (Cloud to Ground) tahun 2018 hasil rekaman sensor Lightning Detector BMKG Stasiun Geofisika Kelas II Gowa dan data luas wilayah per kabupaten dari BPS Provinsi Sulawesi Selatan. Penelitian ini bertujuan untuk mengetahui variasi spasial dan temporal tingkat ancaman sambar...

The mechanism on how lightning detection system (LDS) operated never been exposed by manufacturer since it was confidential. This scenario motivated the authors to explore the issue above by using MATLAB to develop autoanalysis software based on the feature extraction. This extraction is intended for recognizing the parameters in the first return stroke, and compare the measurement between the autoanalysis software and the manual analysis. This paper is a modification based on a previous work regarding autoanalysis of zero-crossing time and initial peak of return stroke using features extraction programming technique. Further, the parameter on rising time of initial peak is added in this autoanalysis programming technique. Finally, the manual analysis using WaveStudio (LeCroy product) of those two lightning parameters is compared with autoanalysis software. This study found that the autoanalysis produce similar result with the manual analysis, hence proved the reliability of this so...

Petir merupakan salah satu fenomena alam yang sangat berbahaya karena energinya yang sangat besar. Setiap kali petir menyambar bisa mengeluarkan energi hingga jutaan volt. Selain itu petir juga selalu bersinggungan dengan kehidupan manusia khususnya petir tipe Cloud to Ground (CG). Kejadian sambaran petir sering menimbulkan kerugian fisik, material bahkan tidak jarang juga menimbulkan korban jiwa.  Provinsi Sulawesi Selatan merupakan salah satu provinsi di Indonesia bagian timur yang cukup padat penduduknya. Dari latar belakang tersebut maka dilakukan penelitian mengenai analisis spasial dan temporal tingkat ancaman sambaran petir CG di wilayah Provinsi Sulawesi Selatan. Penelitian ini menggunakan data petir tipe CG (Cloud to Ground) tahun 2018 hasil rekaman sensor Lightning Detector BMKG Stasiun Geofisika Kelas II Gowa dan data luas wilayah per kabupaten dari BPS Provinsi Sulawesi Selatan. Penelitian ini bertujuan untuk mengetahui variasi spasial dan temporal tingkat ancaman sambar...

We present a procedure for calculating the radiance of TLEs (eg sprites and Elves), based on observations conducted from Israel in the 2008/9 winter season. We developed a reliable and accurate method for calibrating the Watec 902H commercial CCD camera, which is commonly used for TLE research. This method enables radiometric measurements of TLE luminosity and can augment spectral and photometric observations conducted with other instruments. We placed a spectral filter (630-810nm) on the camera and thus the ...

We model lightning leader plasma as bosonic condensate of electrons circulating at the quantum limit. For condensation as a charged superfluid our identical circle arcs join smoothly in Peano-type strings. Throughout chiral refinement stages, scaling string stresses secure self-confinement in leader plasma. Energies of co-circulating hydrogen enter fusion regimes of the isotopes. Atmospheric nitrogen and oxygen reach activation energies of their nuclei in five refinement steps of our string patterns.

We derive an explicit energy-momentum relation for vortex matter combining negative effective mass with self-confining and self-assembling state equations. For periodic vortex flow in the plane we obtain complex potentials in dipolar unit cells for minimal dissipation. In vortex plasma we include electric polarization arising between vortex cores and stagnation points. For periodic vortex flow in space our model uses symmetric stacks of identical cylinders or strings of identical torus or helix tube elements appropriate for a bosonic ground state. We rank their dissipation through filling factors of tube stacks at equal spin angles obtained from platonic solids. A rhombohedral unit cell stacking four cylinders with 3fold symmetry turns out as best fit for linear vortex lattices. For vortex rings we construct cubic lattices with slip-free rolling of unlinked tori, and concatenation without net flux linkage. And right-or left-handed helix elements also build a cubic vortex lattice, with chiral monopoles for open flux tubes, and chiral dipoles for closure into helix rings.

Models for turbulent vortex stretching are presented as differentiable fractal curve constructions with circle arcs and screw segments replacing line elements in the usual definitions of non-analytic Koch- and Peano curves. Examples pf kink-free fractal curves are shown as self-intersecting, self-avoiding or (asymptotically) self-tangent loops, with flat versions partially or fully filling the plane, and spatial versions likewise for three dimensions.
One set of kink-free fractal curves analytically models growing horseshoe vortices in Hinześconceptual model for turbulence near a wall. From random walk analysis of transition layer vorticity on a defective lattice for intermittency, the inverse Von Karman constant emerges as fractal dimension threshold for escape of turbulence to infinity.
A second curve sequence analytically models a vortex ring in superfluid helium stretching into a homogeneous vortex tangle moving between flat walls in a square channel. The deformation rule employs Hilbert's cube-filling loop construction with line segments bent into circle arcs with end points meeting at zero angle. Dynamically, the deformation geometry demands unequal skin friction on adjacent channel walls as boundary condition. The stretching process accelerates circulation velocities exponentially by conservation of angular momentum in vortex tubes with constant core volume.
A third class of curves models deformation of a plasma vortex ring formed by (high-voltage or laser) discharge impact on a flat electrode surface, and carried sideways by turbulent shear flow. The construction rule now uses circle arcs twisted into Hopf-invariant screw segments for the streamlines, with mirror-symmetric halves preserving zero topoligical charge in the loop structure. Dynamically, skin friction from no-slip boundary conditions here exerts parallel torques on leading and trailing ring sections, twisting its right and left halves into mirror images with equal amounts of opposite helicity.

In lightning discharge plasma we find a regime for negative dielectric response known from microwave transmission through tenuous wire grids. From photonic response in vortex plasma we treat ball lightning as a charged eigenstate fully defined by its central potential, and evolving without change in radius and brightness. Helical plasmon waves in spherical vortex crystals enhance self-confinement by interfering like worm gears packed with octahedral symmetry. The thermodynamic limit extends energy levels of its concentric gear shells beyond those of electron shells in the natural elements.

Malaysia is one of the countries with the highest lightning strikes incidence in the world. Yet, Malaysians are still taking a proper lightning protection indifferent manner. This might be due to lack of knowledge on lightning characteristics in Malaysia. Therefore, this study presents an unusual lightning phenomenon with multiple grounding points that might cause a disastrous event, called fork lightning. Between November and December 2018, there were three different patterns of fork lightning mechanism successfully recorded by using high speed camera with 2800 frame per second. Temporal analysis of the lightning progress had been done on the samples based only on the camera records which then played back by using Wondershare Filmora video editor. These three samples of fork lightning images were acquired among 37 lightning events recorded in this study. The first sample of fork lightning fully established the forked branch 0.35 ms before the return stroke occurred. On the contrary...

For the first time, a paper about the existence of isolated bodies of salt water on the Earth's surface was written about three years ago. The reason for this was two unexpected pieces of information from Antarctica. The first indicated that there are salt lakes there that do not freeze to -30°C. The second piece of information was no less interesting. A photo taken from a helicopter in the mountain massif showed a shape with the caption "possible cave".

A remotely manageable optical observation system for recording transient luminous events (TLEs) in the upper atmosphere was installed in Baja, Hungary in 2014. This report describes hardware components and settings of the system, software solutions applied either for realtime event detection and remote control, and the strategy of actually making the observations. An overview on the number and type of TLEs observed up to 2020 is presented. During the 7 years of operation, 1655 TLEs were recorded, 92.7% of which were red sprites, 6.4% were sprite halos, and the set of captured events contained altogether only 3 ELVES. Most sprites were observed in June while most sprite halos were observed in September over the years covered in this report.

This paper presents the characteristic of the positive attempted leaders preceded by positive narrow bipolar pulses (NPBPs). Attempted leaders are the preliminary breakdown process with no subsequent event (return stroke). On the other hand, narrow bipolar pulse is the lightning event commonly isolated and produces a strong electromagnetic field (in a short period). Attempted leaders hardly occurred in the tropics, and the preceding of the NBP (the combination) should be considered unique. In this present study, we found four samples in which the arithmetic means of duration of NPBPs pulse was 32.19 µs, with separation between the positive attempted leader was 1.86 ms apart. For the positive attempted leader, the arithmetic means of the whole pulse train, individual pulse and interval pulse of positive attempted leaders were 3.47 ms, 29.66 µs and 486.53 µs, respectively. The pulse train in this study seems to fade out fast compared to the isolated positive attempted leader pulse tra...

In this study, the lightning current waveforms at the middle and bottom positions for 60 m tall tower strikes were observed using the three-dimensional finite element method (3D-FEM). When creating the model for lightning current waveform analysis at the middle and bottom positions of towers, base current speed and ground conductivity characteristics were taken into account. The model was developed using scattering boundary conditions to avoid wave reflections and limit computation time. We have considered ground conductivity of 5.98 e7 S/m, 0.1 S/m, and 0.01 S/m, respectively, in our model. Base current speeds were considered in our model to be equal to the velocity of light, half of the velocity of light, and one-third of the velocity of light, respectively. This investigation will aid in developing a lightning protection strategy and a better understanding of the properties of lightning.

Las descargas eléctricas atmosféricas que se generan entre las nubes y la ionosfera son fenómenos electromagnéticos que se vienen estudiando sistemáticamente a nivel mundial hace muy poco tiempo, cerca de 30 años. Su interés radica en las radiaciones de muy alta frecuencia (rayos gamma) que son muy diferentes a los rayos que hasta ahora se han estudiado en el rango de las radiofrecuencias. En este artículo se presentan los fenómenos denominados destellos de rayos gamma terrestres (Terrestrial Gamma-ray Flash, TGF) y eventos luminosos terrestres (transient luminous events, TLE), y se analiza el papel de los estudios que lleva a cabo en Colombia el grupo PAAS-UN y los beneficios que esta rigurosa y sistemática investigación representan para el futuro del conocimiento científico de los rayos en el país.

Este artículo sobre la investigación del fenómeno del rayo ha sido elaborado para la posesión como Miembro de Número de la Academia Colombina de Ciencias Exactas, Físicas y Naturales. El fenómeno natural ha sido investigado sistemáticamente en Colombia desde hace aproximadamente cuatro décadas motivado por la curiosidad científica para comprender la alta mortalidad de sistemas, equipos y de personas. Con base en el desarrollo de una hipótesis de investigación se fueron confrontando sus resultados con la realidad concreta, mediante el método científico inductivo y la categoría conceptual de un trabajo interdisciplinario con vínculos dialecticos y la intersección e integración de saberes como la física, las matemáticas, la química, la biología, la historia, la literatura y la psicología social. Con los resultados de investigación se ha logrado aportar nuevo conocimiento del fenómeno en el concierto mundial con libros, artículos científicos, patentes, innovaciones tecnológicas para apl...

Cuando se me propuso escribir un artículo acerca de la investigación que se ha desarrollado en la Universidad Nacional sobre los rayos en Colombia, para una edición especial de la revista de Ingeniería e Investigación con motivo de los 30 años de la creación del programa de Ingeniería Eléctrica, acepto pensando en recopilar y resumir los diferentes artículos técnicos presentados en varios foros sobre el tema y resultados de la investigación. Sin embargo, considero que para una edición especial era más conveniente referirme a la evolución histórica del conocimiento sobre los rayos, partiendo de lo mitológico, planteando lo científico y mostrando mi visión sobre esta investigación en Colombia.

The unusual lightning events are characterized by a pronounced opposite-polarity pulse prior to the main electric field waveform. These electric fields are pertinent to the unusual lightning events recorded in the Himalayan region, at the height of about 1300 m above the sea level, during the premonsoon period of 2015. For the case of unusual events, a downward positive leader approaches the ground, and there is an increase in the downward-directed electric field due to which negative leaders move upwards and will try to intercept. Continuous wavelet transform has been used to understand the features of different events of lightning frequency. The wavelet transform of different events of unusual signals in the present study reveals that the unusual flashes radiate in the spectral range of 1–412.5 kHz in the initial stage and 0.9375–337.5 kHz in the overshoot which conclude that they radiate in very low frequency to very high frequency indicating that they are composed of many microd...

A remotely manageable optical observation system for recording transient luminous events (TLEs) in the upper atmosphere was installed in Baja, Hungary in 2014. This report describes hardware components and settings of the system, software solutions applied either for realtime event detection and remote control, and the strategy of actually making the observations. An overview on the number and type of TLEs observed up to 2020 is presented. During the 7 years of operation, 1655 TLEs were recorded, 92.7% of which were red sprites, 6.4% were sprite halos, and the set of captured events contained altogether only 3 ELVES. Most sprites were observed in June while most sprite halos were observed in September over the years covered in this report.

The environmental conditions leading to the bouncing-wave discharge and the subsequent electron beam remain to be investigated in more detailed future studies. The analysis of quasi-static initial electric field changes (IECs) were found at the beginning of all 24 lightning flashes detected within reversal distance (22 Negative Cloud-to-Ground (–CG) and 2 normal Intra-Cloud (IC) flashes) in a tropical storm on June 15th, 2017 close to our station in Malacca, Malaysia (2.314077° N, 102.318282° E). The IECs durations averaged 4.28 ms for –CG flashes (range 1.48 to 9.45 ms) and averaged 11.30 ms for normal ICs flashes (range 7.24 to 15.35 ms). In comparison to Florida storms, the duration of IECs for –CG and IC flashes were 0.18 ms (range 0.08 to 0.33 ms) and 1.53 ms (range 0.18 to 5.70 ms), respectively. Moreover, the magnitudes of E-change for tropical thunderstorm were 0.13 V/m (range 0.03 to 0.44 V/m) for –CG flashes and -0.20 V/m (range -0.13 to -0.27 V/m) for IC flashes. The E-ch...

This paper reports a recent observation of Narrow Bipolar Event (NBE) occurrence as part of cloud-to-ground flash activity in tropical thunderstorms. Electric field change measurement has been conducted in Southern Malaysia (latitude 1°34ʹ′12.00ʺ″N, longitude 103°38ʹ′42.00ʺ″E) during Northeastern monsoon season between November and December 2012. From the total 173 recorded NBEs, more than half, (60.7%), appeared to occur in isolation; that is, no other lightning flashes occurring prior to or following the NBEs within the record length of 500 ms with a 150 ms pre-trigger delay. The remaining 36.4% of NBEs have been observed to occur as part of cloud-to-ground flash activity. We found that more than one third of NBEs with cloud-to-ground flash, about 38.1% have occurred between return strokes. Both polarities of NBEs (+NBE and –NBE) were recorded between the return strokes. The other one third of NBEs, about 36.5% have been observed to follow the last return stroke with both polariti...