scholarly journals Ground to Cloud Lightning Flash Currents and Electric Fields: Interaction with Aircraft and Production of Ionosphere Sprites

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
P. R. P. Hoole ◽  
S. Thirukumaran ◽  
Harikrishnan Ramiah ◽  
Jeevan Kanesan ◽  
S. R. H. Hoole
Keyword(s):  
Frequency Spectrum ◽  
Electric Fields ◽  
Electric Circuit ◽  
Ground Level ◽  
Transverse Magnetic ◽  
Lightning Flash ◽  
Electric Discharges ◽  
Electric Currents ◽  
Safety Testing ◽  
Cloud To Ground Lightning

This paper presents for the first time a case for the importance of ground to cloud (upward leader) lightning flash parameters for safety testing of direct aircraft-lightning interaction and protection of wind turbines, as well as the importance of radiated electric fields for indirect lightning-aircraft interaction and generation of electric discharges called sprites and halos in the ionosphere. By using an electric circuit model of the transverse magnetic waves along the return stroke channel, electric currents at ground level as well as cloud level are determined for both the cloud to ground lightning flash and the ground to cloud lightning flash. We show that when an aircraft triggers lightning, the electric currents will be much more severe in current magnitude, rate of rise of currents, and frequency spectrum than otherwise and are more severe than the parameters observed for the usual and well monitored (and measured) cloud to ground (downward leader) flashes. The rate of rise of currents and the frequency spectrum of the ground to cloud lightning flash are also given here. The electric fields radiated by the lightning flashes that would appear in the ionosphere are presented for both the earth flash and the ground to cloud flash.

scholarly journals Ampere's Magnetic Circuital Law: A Simple and Rigorous Two-Step Proof

2001 ◽  
Vol 38 (3) ◽  
pp. 246-255 ◽  
Author(s):  
K. C. Rajaraman
Keyword(s):  
Magnetic Field ◽  
Electric Fields ◽  
Physical Interpretation ◽  
Free Space ◽  
Electric Circuit ◽  
Second Step ◽  
Mathematical Treatment ◽  
Electric Currents ◽  
Magnetic Effects ◽  
The Magnetic Field

A new proof of Ampere's law from the Biot-Savart law is presented. In the first step, a physical interpretation of current as moving charges carrying their electric fields with them simplifies the derivation of the magnetic field of current in a straight infinitely long conductor. The m.m.f. of a finite electric circuit linking a magnetic path is synthesized from those of two infinitely long wires carrying equal currents in opposite directions, only one of them threading the path. This makes the second step rigorous, enabling a non-mathematical treatment of the magnetic effects of electric currents in free space.

Investigation of Zero Crossing Detection for First Return Stroke in Negative Cloud-to-Ground Lightning Flash

2019 ◽  
Vol 11 (3) ◽  
Author(s):  
Ahmad Idil Abd Rahman ◽  
◽  
Muhammad Akmal Bahari ◽  
Zikri Abadi Baharudin ◽  
◽  
...  
Keyword(s):  
Lightning Flash ◽  
Return Stroke ◽  
Zero Crossing ◽  
Cloud To Ground Lightning

A Case for Magneto Hydro Dynamics (MHD)

2001 ◽  
Author(s):  
Haim H. Bau
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Magnetic Flux ◽  
Lorentz Force ◽  
Electric Fields ◽  
Biological Fluids ◽  
Fluid Volume ◽  
Chaotic Advection ◽  
Complex Flows ◽  
Electric Currents

Abstract In this paper, I review some of our work on the use of magneto hydrodynamics (MHD) for pumping, controlling, and stirring fluids in microdevices. In many applications, one operates with liquids that are at least slightly conductive such as biological fluids. By patterning electrodes inside flow conduits and subjecting these electrodes to potential differences, one can induce electric currents in the liquid. In the presence of a magnetic field, a Lorentz force is generated in a direction that is perpendicular to both the magnetic and electric fields. Since one has a great amount of freedom in patterning the electrodes, one can induce forces in various directions so as to generate complex flows including “guided” flows in virtual, wall-less channels. The magnetic flux generators can be either embedded in the device or be external. Despite their unfavorable scaling (the magnitude of the forces is proportional to the fluid volume), MHD offers many advantages such as the flexibility of applying forces in any desired direction and the ability to adjust the magnitude of the forces by adjusting either the electric and/or magnetic fields. We provide examples of (i) MHD pumps; (ii) controlled networks of conduits in which each conduit is equipped with a MHD actuator and by controlling the voltage applied to each actuator, one can direct the liquid to flow in any desired way without a need for valves; and (iii) MHD stirrers including stirrers that exhibit chaotic advection.

scholarly journals Effects of Underground Cavities on the Frequency Spectrum of Seismic Shear Waves

2014 ◽  
Vol 2014 ◽  
pp. 1-17 ◽  
Author(s):  
G. Lancioni ◽  
R. Bernetti ◽  
E. Quagliarini ◽  
L. Tonti
Keyword(s):  
Frequency Spectrum ◽  
Ad Hoc ◽  
Parametric Design ◽  
Shear Waves ◽  
Scattering Problem ◽  
Ground Surface ◽  
Ground Level ◽  
Seismic Shear ◽  
Underground Cavities ◽  
Free Wave Propagation

A numerical method is proposed to study the scattering of seismic shear waves induced by the presence of underground cavities in homogeneous soils. The method is based on the superposition of two solutions: the solution of the free-wave propagation problem in a uniform half-space, easily determined analytically, and the solution of the wave scattering problem due to the cave presence, evaluated numerically by means of an ad hoc code implemented by using the ANSYS Parametric Design Language. In the two-dimensional setting, this technique is applied to the case of a single cave, placed at a certain depth from the ground level. The frequency spectrum of the seismic shear oscillation on the ground surface is determined for different dimensions and depths of the cave and compared with the spectrum registered without caves. The influence of the cave dimensions and depth on the spectrum amplification is analyzed and discussed.

scholarly journals The Global Electric Circuit and Global Seismicity

Geosciences ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 491
Author(s):  
Sergey Pulinets ◽  
Galina Khachikyan
Keyword(s):  
Electric Fields ◽  
Ground Surface ◽  
Electric Circuit ◽  
Thunderstorm Activity ◽  
Radon Emanation ◽  
Global Electric Circuit ◽  
Important Conclusion ◽  
Earthquake Preparation ◽  
Deep Focus ◽  
Ionospheric Potential

Basing on the catalogue of earthquakes with a magnitude of M ≥ 4.5 for the period 1973–2017, a UT variation with an amplitude of ~10% in the number of earthquakes is revealed and compared with a UT variation in the ionospheric potential (IP) with an amplitude of ~18%. We demonstrate that the amplitude of the UT variation in the number of deep-focus earthquakes is greater compared with that of crustal earthquakes, reaching 19%. The UT of the primary maxima of both the IP (according to modern calculations) and of earthquake incidence coincides (near 17:00 UT) and is, by 2 h, ahead of the classical Carnegie curve representing the UT variation in the atmospheric electric field on the ground surface. The linear regression equation between these UT variations in the number of deep-focus earthquakes and the ionospheric potential is obtained, with a correlation coefficient of R = 0.97. The results support the idea that the processes of earthquake preparation are coupled to the functional processes of the global electric circuit and the generation of atmospheric electric fields. In particular, the observed increase in thunderstorm activity over earthquake preparation areas, provided by air ionization due to radon emanation, yields a clue as to why the global thunderstorm distribution is primarily continental. Another important conclusion is that, in observing the longitudinal distributions of earthquakes against the IP distribution, we automatically observe that all such events occur in local nighttime hours. Considering that the majority of earthquake precursors have their maximums at local night and demonstrating the positive deviation from the undisturbed value, we obtain a clue as to its positive correlation with variations in the ionospheric potential.

An Isolated Winter Cloud-to-Ground Lightning Flash Causing Damage and Injury in Connecticut

1997 ◽  
Vol 78 (3) ◽  
pp. 437-441 ◽  
Author(s):  
Ronald L. Holle ◽  
Raúl E. López ◽  
Kenneth W. Howard ◽  
Kenneth L. Cummins ◽  
Mark D. Malone ◽  
...  
Keyword(s):  
Lightning Flash ◽  
Cloud To Ground Lightning

Cloud-to-Ground Lightning Flash Characteritics in Meteorogical Conditions

1997 ◽  
Author(s):  
R.B.B. Gin ◽  
O. Pinto Jr. ◽  
I.R.C.A. Pinto ◽  
O. Mendes Jr.
Keyword(s):  
Lightning Flash ◽  
Cloud To Ground Lightning
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