scholarly journals Lightning for Energy and Material Uses: A Structured Review

2020 ◽  
Author(s):  
Daniel S. Helman
Keyword(s):  
Lightning Discharge ◽  
Atmospheric Electricity ◽  
Dusty Plasmas ◽  
Biomass Energy ◽  
Separation Processes ◽  
New Class ◽  
Surface Charging ◽  
Oceanic Surface ◽  
Triggered Lightning ◽  
Early Translation

The average atmospheric charge density of Earth is neutral. Charge built up from thunderstorms and lightning phenomena is offset by oceanic surface charging, and offers a source of energy that has not been harnessed broadly. Unfortunately, the total terrestrial energy of the Earth’s atmospheric electrical system is modest (250–500 MW) compared to industrial requirements: Innovations are likely to offer improvements to societal efficiency rather than broad transformations. Direct capture systems located in places with very high occurrence of lightning discharge can generate ≈1 kWh per year on average. Material processing via triggered lightning is limited to techniques that utilize rapid discharges, e.g., metal and glass preprocessing of materials, waste volume reduction, biomass energy conversion, where current prices make plasma‐arc processes prohibitive. Triggered lightning may be used to assist blasting of mountain rock; or as a high‐voltage input for processes such as nuclear fusion. Passive collection of atmospheric electricity is modest but may be used in urban agriculture to increase biomass production. Thunderstorm charge‐separation processes suggest a new class of electricity generators based on kinetic energy and material collision. Ball lightning suggests additional research in dusty plasmas. These methods are all at proof‐of‐concept or early translation stages.

scholarly journals A performance analysis of the North American Lightning Detection Network using CN Tower lightning data

2021 ◽  
Author(s):  
Alexandru Lafkovici
Keyword(s):  
North American ◽  
Detection Efficiency ◽  
Lightning Discharge ◽  
Location Error ◽  
Error Ellipse ◽  
Semi Major Axis ◽  
North East ◽  
The North ◽  
Lightning Detection ◽  
Triggered Lightning

The North American Lightning Detection Network (NALDN) is a commercial lightning detection network operated by Vaisala Inc., and is composed of the U.S. National Lightning Detection Network (NLDN) and the Environment Canada owned Canadian Lightning Detection Network (CLDN). The CN Tower is one of the best sites in the world to observe the lightning phenomenon and provides an excellent opportunity to evaluate the performance of the NALDN in the Toronto area. Using CN Tower lightning data acquired during 2005, the performance characteristics of the NALDN were thoroughly evaluated, including the flash detection efficiency (DE), stroke DE, absolute location error, peak current estimation and location accuracy model (50%, 90% and 99% error ellipses) error. Although a similar test was performed using rocket-triggered lightning in Florida at Camp Blanding, this test evaluated a completely different region of the NALDN. Moreover, rocket-triggered lightning artificially initiates a lightning discharge, whereas lightning events to the CN Tower occur naturally and are similar to discharges that occur to tall structures or objects at high altitude or mountainous areas. Excluding two flashes understood to be composed of M-components, the NALDN detected 7 out of 7 flashes recorded at the CN Tower, resulting in a 100% flash DE. Furthermore, the NALDN detected 22 out of 39 strokes recorded at the CN Tower, resulting in a stroke DE of 56%. Relative to the CN Tower, the NALDN was found to have a median absolute location error of 0.356 km and a mean error of 0.390 km for the 22 strokes it detected. It was also demonstrated that the NALDN stroke location error seems to have a large bias towards the north of the CN Tower and a slight bias towards the east, with 19 of the 22 strokes predicted north-east of the CN Tower. The 50%, 90% and 99% error ellipses provided by the NALDN were also evaluated. It was found that 73% (16 out of the 22) detected strokes were enclosed by the 50% error ellipse, 91% (20 out of the 22) detected strokes were enclosed by the 90% error ellipse and 95% (21 out of the 22) detected strokes were enclosed by the 99% error ellipse. The minimum value for the 50% error ellipse axes is set at 0.4 km by Vaisala, and 21 out of the 22 detected strokes had a semi-major axis length of 0.4 km, suggesting that the median location error for CN Tower strokes is 0.4 or less. The 0.356 km median location error obtained for the 22 detected strokes appears to support this.

scholarly journals Evolution Characteristics during Initial Stage of Triggered Lightning Based on Directly Measured Current

Atmosphere ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 658
Author(s):  
Zefang Chen ◽  
Yang Zhang ◽  
Yanfeng Fan ◽  
Jingxuan Wang ◽  
Dong Zheng ◽  
...  
Keyword(s):  
Lightning Discharge ◽  
Ground Level ◽  
Current Data ◽  
Discharge Process ◽  
Measured Current ◽  
Critical Range ◽  
Initial Stage ◽  
Evolution Characteristics ◽  
Triggered Lightning ◽  
Initial Process

The initiation of a leader is an important lightning discharge process, but how an upward positive leader (UPL) initiates is still not fully understood. The evolution characteristics of a UPL during its initial stage was systematically studied based on directly measured current data of 14 triggered lightning events in 2019. It was found that the initial stage of triggered lightning can be divided into two types: a single initial process form and a multiple initial process form, with percentages of 64.29% and 35.71%, respectively. Compared with the former, the latter usually lasts longer, and the corresponding lightning is often triggered under a lower ground-level quasi-static electric field. In each initial process, precursor current pulses (PCPs), PCP clusters and initial precursor current pulse (IPCPs) are typical current waveforms, and the pulse durations and transferred charges of PCPs increase linearly with time. However, in the multiple initial process form, the pulse durations and transferred charges of PCPs will reduce significantly after each previous initial process and then continue to increase in the following initial process. In each initial process, when the pulse duration and transferred charge of a PCP increase to a certain extent, PCP clusters and IPCPs begin to appear. For the emergence of PCP clusters, the average values of the threshold are 3.48 μs and 19.53 μC, respectively. For the occurrence of IPCPs, the corresponding values are 4.69 μs and 27.23 μC, respectively. The average values of pulse durations and transferred charges of IPCPs are larger than those of PCP clusters. Compared with adjacent PCP clusters, IPCPs contain more pulses, with a critical range of 6–7. IPCPs also last longer, and have a critical range of 138–198 μs.

scholarly journals Colour-producing β-keratin nanofibres in blue penguin ( Eudyptula minor ) feathers

2011 ◽  
Vol 7 (4) ◽  
pp. 543-546 ◽  
Author(s):  
Liliana D'Alba ◽  
Vinodkumar Saranathan ◽  
Julia A. Clarke ◽  
Jakob A. Vinther ◽  
Richard O. Prum ◽  
...  
Keyword(s):  
Self Assembly ◽  
Coherent Scattering ◽  
Two Dimensional ◽  
Collagen Fibres ◽  
Separation Processes ◽  
New Class ◽  
X Ray Scattering ◽  
Absorption Of Light ◽  
Physical Interactions ◽  
Living Organisms

The colours of living organisms are produced by the differential absorption of light by pigments (e.g. carotenoids, melanins) and/or by the physical interactions of light with biological nanostructures, referred to as structural colours. Only two fundamental morphologies of non-iridescent nanostructures are known in feathers, and recent work has proposed that they self-assemble by intracellular phase separation processes. Here, we report a new biophotonic nanostructure in the non-iridescent blue feather barbs of blue penguins ( Eudyptula minor ) composed of parallel β-keratin nanofibres organized into densely packed bundles. Synchrotron small angle X-ray scattering and two-dimensional Fourier analysis of electron micrographs of the barb nanostructure revealed short-range order in the organization of fibres at the appropriate size scale needed to produce the observed colour by coherent scattering. These two-dimensional quasi-ordered penguin nanostructures are convergent with similar arrays of parallel collagen fibres in avian and mammalian skin, but constitute a novel morphology for feathers. The identification of a new class of β-keratin nanostructures adds significantly to the known mechanisms of colour production in birds and suggests additional complexity in their self-assembly.

scholarly journals Fast and Fine Location of Total Lightning from Low Frequency Signals Based on Deep-Learning Encoding Features

2021 ◽  
Vol 13 (11) ◽  
pp. 2212
Author(s):  
Jingxuan Wang ◽  
Yang Zhang ◽  
Yadan Tan ◽  
Zefang Chen ◽  
Dong Zheng ◽  
...  
Keyword(s):  
Deep Learning ◽  
Signal To Noise Ratio ◽  
Lightning Discharge ◽  
Low Frequency ◽  
New Method ◽  
Discharge Process ◽  
Matching Efficiency ◽  
Triggered Lightning ◽  
Artificial Intelligence Technology ◽  
Total Lightning

Lightning location provides an important means for the study of lightning discharge process and thunderstorms activity. The fine positioning capability of total lightning based on low-frequency signals has been improved in many aspects, but most of them are based on post waveform processing, and the positioning speed is slow. In this study, artificial intelligence technology is introduced for the first time to lightning positioning, based on low-frequency electric-field detection array (LFEDA). A new method based on deep-learning encoding features matching is also proposed, which provides a means for fast and fine location of total lightning. Compared to other LFEDA positioning methods, the new method greatly improves the matching efficiency, up to more than 50%, thereby considerably improving the positioning speed. Moreover, the new algorithm has greater fine-positioning and anti-interference abilities, and maintains high-quality positioning under low signal-to-noise ratio conditions. The positioning efficiency for return strokes of triggered lightning was 99.17%, and the standard deviation of the positioning accuracy in the X and Y directions was approximately 70 m.

scholarly journals Application of Genetic Algorithm to Estimation of Function Parameters in Lightning Currents Approximations

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
V. Javor ◽  
K. Lundengård ◽  
M. Rančić ◽  
S. Silvestrov
Keyword(s):  
Genetic Algorithm ◽  
Power Systems ◽  
Lightning Discharge ◽  
Lightning Protection ◽  
Lightning Stroke ◽  
Vertical Antenna ◽  
Stroke Models ◽  
Triggered Lightning ◽  
Extended Function ◽  
Good Agreement

Genetic algorithm (GA) is applied for the estimation of two-peaked analytically extended function (2P-AEF) parameters in this paper. 2P-AEF is used for approximation of measured and typical lightning discharge currents. Lightning discharge channel is often modeled as thin-wire vertical antenna at perfectly conducting ground. Engineering lightning stroke models assume that the current along that channel is related to the channel-base current which may be measured at the instrumented tall towers and in triggered lightning experiments. Mathematical modeling of lightning currents is important in verification of lightning strokes models based on simultaneously measured electromagnetic fields at various distances, so as in lightning protection studies, computation of lightning induced effects and simulation of overvoltages in power systems. Typical lightning discharge currents of the first positive, first negative, and subsequent negative strokes are defined by IEC 62305 Standard based on comprehensive measurements. Parameters of 2P-AEF’s approximation of the typical negative first stroke current are determined by GA and compared to approximations obtained by other functions. Measured currents at Monte San Salvatore in Switzerland, at Morro de Cachimbo Station in Brazil, and in rocket-triggered lightning experiments at Camp Blanding in Florida are approximated by 2P-AEFs, and good agreement with experimentally measured waveshapes is obtained.

scholarly journals A performance analysis of the North American Lightning Detection Network using CN Tower lightning data

2021 ◽  
Author(s):  
Alexandru Lafkovici
Keyword(s):  
North American ◽  
Detection Efficiency ◽  
Lightning Discharge ◽  
Location Error ◽  
Error Ellipse ◽  
Semi Major Axis ◽  
North East ◽  
The North ◽  
Lightning Detection ◽  
Triggered Lightning

The North American Lightning Detection Network (NALDN) is a commercial lightning detection network operated by Vaisala Inc., and is composed of the U.S. National Lightning Detection Network (NLDN) and the Environment Canada owned Canadian Lightning Detection Network (CLDN). The CN Tower is one of the best sites in the world to observe the lightning phenomenon and provides an excellent opportunity to evaluate the performance of the NALDN in the Toronto area. Using CN Tower lightning data acquired during 2005, the performance characteristics of the NALDN were thoroughly evaluated, including the flash detection efficiency (DE), stroke DE, absolute location error, peak current estimation and location accuracy model (50%, 90% and 99% error ellipses) error. Although a similar test was performed using rocket-triggered lightning in Florida at Camp Blanding, this test evaluated a completely different region of the NALDN. Moreover, rocket-triggered lightning artificially initiates a lightning discharge, whereas lightning events to the CN Tower occur naturally and are similar to discharges that occur to tall structures or objects at high altitude or mountainous areas. Excluding two flashes understood to be composed of M-components, the NALDN detected 7 out of 7 flashes recorded at the CN Tower, resulting in a 100% flash DE. Furthermore, the NALDN detected 22 out of 39 strokes recorded at the CN Tower, resulting in a stroke DE of 56%. Relative to the CN Tower, the NALDN was found to have a median absolute location error of 0.356 km and a mean error of 0.390 km for the 22 strokes it detected. It was also demonstrated that the NALDN stroke location error seems to have a large bias towards the north of the CN Tower and a slight bias towards the east, with 19 of the 22 strokes predicted north-east of the CN Tower. The 50%, 90% and 99% error ellipses provided by the NALDN were also evaluated. It was found that 73% (16 out of the 22) detected strokes were enclosed by the 50% error ellipse, 91% (20 out of the 22) detected strokes were enclosed by the 90% error ellipse and 95% (21 out of the 22) detected strokes were enclosed by the 99% error ellipse. The minimum value for the 50% error ellipse axes is set at 0.4 km by Vaisala, and 21 out of the 22 detected strokes had a semi-major axis length of 0.4 km, suggesting that the median location error for CN Tower strokes is 0.4 or less. The 0.356 km median location error obtained for the 22 detected strokes appears to support this.

Observations of the initial, upward-propagating, positive leader steps in a rocket-and-wire triggered lightning discharge

2011 ◽  
Vol 38 (24) ◽  
pp. n/a-n/a ◽  
Author(s):  
Christopher J. Biagi ◽  
M. A. Uman ◽  
J. D. Hill ◽  
D. M. Jordan
Keyword(s):  
Lightning Discharge ◽  
Triggered Lightning
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