scholarly journals EVALUATION OF ELECTROMAGNETIC FIELDS ASSOCIATED WITH INCLINED LIGHTNING CHANNEL USING SECOND ORDER FDTD-HYBRID METHODS

2011 ◽  
Vol 117 ◽  
pp. 209-236 ◽  
Author(s):  
Mahdi Izadi ◽  
Mohd Zainal Abidin Ab Kadir ◽  
Chandima Gomes
Keyword(s):  
Electromagnetic Fields ◽  
Hybrid Methods ◽  
Second Order ◽  
Lightning Channel

scholarly journals Direct Solution of Second Order Ordinary Differential Equations Using a Class of Hybrid Block Methods

2020 ◽  
Vol 5 (2) ◽  
Author(s):  
Emmanuel A Areo ◽  
Nosimot O Adeyanju ◽  
Sunday J Kayode
Keyword(s):  
Initial Value Problems ◽  
Hybrid Methods ◽  
Multistep Method ◽  
Second Order ◽  
Block Method ◽  
Initial Value ◽  
Order Error ◽  
Block Methods ◽  
Grid Points ◽  
Step Number

This research proposes the derivation of a class of hybrid methods for solution of second order initial value problems (IVPs) in block mode. Continuous linear multistep method of two cases with step number k = 4 is developed by interpolating the basis function at certain grid points and collocating the differential system at both grid and off-grid points. The basic properties of the method including order, error constant, zero stability, consistency and convergence were investigated. In order to examine the accuracy of the methods, some differential problems of order two were solved and results generated show a better performance when comparison is made with some current methods.Keywords- Block Method, Hybrid Points, Initial Value Problems, Power Series, Second Order 

Current and radiated electromagnetic fields due to lightning return strokes when hitting elevated objects

2016 ◽  
Vol 35 (3) ◽  
Author(s):  
Maryam Hajebi ◽  
Mojtaba Khosravi-Farsani ◽  
Seyed Hossein Hesamedin Sadeghi ◽  
Rouzbeh Mazandarani Moini
Keyword(s):  
Electromagnetic Fields ◽  
Current Distribution ◽  
Design Methodology ◽  
Fdtd Method ◽  
Measurement Data ◽  
Vertical Component ◽  
Uniform Mesh ◽  
Large Space ◽  
Lightning Channel ◽  
The Impact

Purpose Tall towers have a high potential for being struck by lightning which is a major source of electromagnetic radiation with adverse effects on electric, electronic and telecommunication instruments. The paper aims to present an accurate method for predicting the radiated electromagnetic fields and current distribution along the lightning channel and the tower hit by the lightning. Design/methodology/approach The electromagnetic model is utilized to model the lightning channel and the tower is represented by lossy conducting wires. The finite difference time domain (FDTD) method is used to solve for the governing Maxwell’s equations. Due to the large computational space, the FDTD code is paralleled between several computer processors. To enhance the efficiency of the code, a non-uniform mesh is used, reducing the mesh length in the air-ground interface. For model evaluation, simulated current distribution along the lightning channel and tower, and the radiated electromagnetic fields are compared with the measurement data and those obtained using the engineering models. Findings The proposed modeling technique has proved to be more accurate than the conventional methods, particularly in the prediction of current distribution along the tall tower and the vertical component of the radiated electric field. Originality/value The main feature of the proposed technique is its ability to consider the impact of metallic structures in a large space around lightning channel on the predicted radiated electromagnetic fields, having no concern on computer memory requirements.

On the effective Lagrangian for scalar electrodynamics

1985 ◽  
Vol 63 (3) ◽  
pp. 431-434 ◽  
Author(s):  
Abul Mansur Chowdhury ◽  
Gerry McKeon
Keyword(s):  
Electromagnetic Field ◽  
Electromagnetic Fields ◽  
Vector Fields ◽  
Quantum Fluctuations ◽  
External Electromagnetic Field ◽  
Second Order ◽  
Type Approximation ◽  
Effective Lagrangian ◽  
Scalar And Vector Fields ◽  
The One

The one-loop effective Lagrangian in scalar electrodynamics is computed using an expansion to second order in the external electromagnetic field and a WKB-type approximation. Quantum fluctuations of both the scalar and vector fields about background scalar and electromagnetic fields are considered.

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