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Microwave Remote Sensing Based on Maxwell Equations
Published in Maged Marghany, Automatic Detection Algorithms of Oil Spill in Radar Images, 2019
Thus, the energy density of the electric field is the same as the energy density of the magnetic field everywhere in the electromagnetic wave. Consequently, we can express the instantaneous power per unit area of an electromagnetic wave in terms of the magnitude of the electric field or that of the magnetic field. Finally, the magnitude of S→ is correlated to the immediate rate at which energy is conveyed by an electromagnetic wave over a specified area, or more simply, the immediate power per unit area. Consequently, the units of the Poynting vector are thus watts per square meter (W/m2). For instance, the value of S→ invisible light range from a few W/m2 in a faint light of a candle to many MW/m2 in the most intense laser beams [5,17,20].
P
Published in Philip A. Laplante, Comprehensive Dictionary of Electrical Engineering, 2018
power system damping a torque action which works to reduce power system oscillations as time progresses. power system oscillation variations in the machine rotor angle caused by small disturbances in the system. The oscillations are usually at low frequency. power system security an operational index that determines the capability of a system to withstand equipment failures and external disturbances. It could be measured by the reserve capacity available or the number of operating constraint violations under a given prevailing condition or under a contingent probability of disturbances. power system stabilizer a control device that provides an additional input signal to the AVR to damp power system oscillations. power transfer function any function of input to output power in ratio form, expressed as a dimensionless ratio. power transformer a transformer that is used to transmit power from one voltage level to another. Power transformers can be of either single phase or three phase design, and include either two or three windings. Poynting vector a vector, proportional to the cross product between the electric and magnetic field intensity vectors, indicating the density and flow of electromagnetic power.
Application of Finite Element Method for the Design of Nanocomposites
Published in Sarhan M. Musa, Computational Finite Element Methods in Nanotechnology, 2013
is the low reflecting boundary condition to model the imaginary source surface where the incident EM wave E0=E→0e→z is emitted and that is transparent to the reflected waves. The Poynting vector π→ is defined as the cross product of the electric and magnetic vectors π→=1/2Re{E→xH}.
Paraxial propagation of the first-order chirped Airy vortex beams propagating in a quadratic index media
Published in Journal of Modern Optics, 2020
Lixun Wu, Yaohui Chen, Xinxiang Lai, Zhixiong Mo, Dongmei Deng
To analyze the propagation properties of electromagnetic fields, we investigate the Poynting vector and the angular momentum of the FCAiV beams through the quadratic index media. As we know, the Poynting vector is the vector of the energy flux density in the electromagnetic field, which is usually used to indicate the direction of the energy flow. The Poynting vector can be defined as [33], where is the light velocity in a vacuum, and are the electric and magnetic fields respectively. Considering an -polarized vector potential , where is the unit vector along the x-direction, the time-averaged Poynting vector can be described as [34] Here and are the unit vectors along the and directions, respectively, and denotes the complex conjugate, is the angular frequency.
Propagation properties of collinear self-decelerating Airy–Elegant–Laguerre–Gaussian wave packets in free space
Published in Journal of Modern Optics, 2019
The Poynting vector is a commonly known quantity in electrodynamics, which means the rate of electromagnetic energy flow per unit area. Figures 5 and 6 show the Poynting vector of the collinear self-decelerating AiELG wave packets in free space in spatial dimension.