Imaging of electrostatic field vector distribution

2021 ◽  
Vol 92 (5) ◽  
pp. 053704
Author(s):  
M. Tsuchiya

During late Tertiary time, the secular variation of the geomagnetic field vector at a number of widely separated sites can be modelled as the sum of the field vector of a randomly sampled isotropic normal dipole moment and a non-dipole field vector that is a function of the assumed source geometry. Here, the non-dipole field vector distribution is calculated in the limit for an infinite number of radial dipole sources on the core surface with a possible latitudinal bias in geographic distribution and a normal moment distribution that is invariant with respect to geographic location. The model therefore consists of four degrees of freedom, and for the usual case of unit vector data the number reduces to three because the dipole variance the and non-dipole source moment variance can be specified only as their ratios to the mean dipole moment. The resultant non-dipole field vectors are non-isotropically normal with zero mean (if and only if the mean of the source moment distribution is everywhere zero). For the assumed source geometry, the dipole—non-dipole sum is normally distributed with mean and covariance as functions of latitude. For direct comparison with the available directional data, the normal distribution is integrated over all possible vector magnitudes to yield the associated unconditional (unit vector) distribution.


1999 ◽  
Vol 119 (8-9) ◽  
pp. 1097-1102
Author(s):  
Haruo Ihori ◽  
Kenichi Ikeda ◽  
Masaharu Fujii ◽  
Kiyomitsu Arii

2021 ◽  
Vol 11 (24) ◽  
pp. 12045
Author(s):  
Josef Novák

The polarization of the piezoelectric resonator depends on the direction of the applied electric field. The direction of the applied electric field is determined by the shape of the resonator and the position of the electrodes. In case of resonators with electrodes incompletely covering their bases, an inhomogeneous electric field is generated, which results in an inhomogeneous polarization of the resonator. The resonator will be polarized in some places either in a direction other than the desired one or not polarized at all. The aim of this work is to analyze the polarization process on resonators with electrodes incompletely covering their bases. The physical description is given by the linear piezoelectric equations, the Gaussian equation for the description of the electric field and by Newton’s law of force. On this basis, a FEM model is developed and used to analyze the polarization process. The results of the calculation of the electric field vector distribution are presented. Finally, the areas are identified in which polarization in the desired direction is achieved in the resonator as well as the ones where no polarization occurs.


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