Surface current density K: an introduction

McAllister, I.W.

doi:10.1109/14.85112

Cited by 10 publications

(9 citation statements)

References 3 publications

(3 reference statements)

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“…For the illustrative purposes of this paper the volume conductivity is set to 10 -13 S/m [2] for the epoxy resin, 10 -15 S/m for the LDPE [17] and 10 -14 S/m for the air [18]. The surface conductivity is set to be equal to the volume conductivity of the dielectric multiplied by 1 km, which is based on a discussion of the properties of epoxy resin in [6]. In both examples the values of bulk conductivity were unimportant, the dynamics of the surface charge were dominated by surface conductivity.…”

Section: Decay Of Deposited Charge In Ac Pd Systemsmentioning

confidence: 99%

“…Within the electrical engineering community the majority of the research on surface charge dynamics can be traced back to work performed by McAllister in the 1980's and 1990 [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

“…The purpose of this paper is to present a method to calculate surface charge density dynamics. Much of the original literature on the subject, [6], does not lend itself to simulation techniques using standard simulation tools. This work has adopted equivalent analytical methodology, [12], which allows the use of a commercial package to provide a numerical solution which facilitates simulating surface charge dynamics for a range of systems.…”

Section: Introductionmentioning

confidence: 99%

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Simulating Surface Charge Dynamics

George

Goddard

Lewin

2021

IEEE Trans. Dielect. Electr. Insul.

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Surface charge dynamics can play an important role in electric field distributions in both AC and DC insulation systems. In this paper the theory behind surface charge dynamics is introduced with a particular focus on the calculation of surface divergence; an operator which is used to determine movement of charge constrained to a surface. A detailed discussion of the model implementation is provided and validated against an analytical solution. Surface charge dynamics in AC and DC insulation systems are then investigated. Assuming the measurement data in the literature is representative it is demonstrated that surface currents have the capability to significantly alter electric field distributions in voids, even over the timescales of an AC cycle.

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Section: Decay Of Deposited Charge In Ac Pd Systemsmentioning

confidence: 99%

“…Within the electrical engineering community the majority of the research on surface charge dynamics can be traced back to work performed by McAllister in the 1980's and 1990 [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Simulating Surface Charge Dynamics

George

Goddard

Lewin

2021

IEEE Trans. Dielect. Electr. Insul.

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“…For the derivation of equation (2.6), we use the concept of surface conductivity [28], while regarding the thin membrane as a two-dimensional surface, because the induced current density along the thin membrane can be viewed as a tangent vector field on the surface. If the deformed membrane is uniform in thickness, the resulting potential v p satisfies the surface Laplace equation, Δ S v p = 0, along the surface with Δ S being the Downloaded 08/22/15 to 132.239.1.231.…”

Section: Formulation Of the Forward Problemmentioning

confidence: 99%

A Pressure Distribution Imaging Technique with a Conductive Membrane using Electrical Impedance Tomography

Ammari

Kang²,

Lee

et al. 2015

SIAM J. Appl. Math.

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This paper presents a mathematical framework for a flexible pressure sensor model using electrical impedance tomography (EIT). When pressure is applied to a conductive membrane patch with clamped boundary, the pressure-induced surface deformation results in a change in the conductivity distribution. This change can be detected in the current-voltage data (i.e., EIT data) measured on the boundary of the membrane patch. Hence, the corresponding inverse problem is to reconstruct the pressure distribution from the data. Assuming that the material's conductivity distribution is constant, we derive a two-dimensional (2D) apparent conductivity (in terms of EIT data) corresponding to the surface deformation. Since the 2D apparent conductivity is found to be anisotropic, we consider a constrained inverse problem by restricting the coefficient tensor to the range of the map from pressure to the 2D apparent conductivity. This paper provides theoretical grounds for mathematically modeling the inverse problem. We develop a reconstruction algorithm based on a careful sensitivity analysis. We demonstrate the performance of the reconstruction algorithm through numerical simulations to validate its feasibility for future experimental studies. Introduction.There is a growing demand for cost-effective flexible pressure sensors. These devices have wide potential applicability, including in smart textiles [7,26,27], touch screens [18], artificial skins [35], and wearable health monitoring technologies [25,29]. Electrical measurements have recently been used to monitor the pressure-induced surface deformation of conductive membranes. In particular, electrical impedance tomography (EIT) has been used to develop flexible pressure sensors [31,37,38], because it allows the electromechanical behavior of an electrically conducting film to be monitored. When a pressure-sensitive conductive sheet is exposed to pressure, the deformation of the surface alters the conductivity distribution, which can be detected by an EIT system. However, rigorous studies employing mathematical modeling and reconstruction methods have not yet been conducted. The purpose of this paper is to provide a systematic mathematical framework for an EIT-based flexible pressure sensor.Our rigorous mathematical analysis is based on the consideration of a simple model of an EIT-based pressure sensor using a thin, flexible conductive membrane

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“…Due to charge conservation, the electric current density must obey the continuity equation, for zero charge density, both inside and on the surface of the conductors [14]:…”

Section: Minimum Magnetic Energy Theoremmentioning

confidence: 99%

Magnetic Field and Current Are Zero Inside Ideal Conductors

Fiolhais¹,

Essén²,

Providência³

et al. 2011

PIER B

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Abstract-We prove a theorem on the magnetic energy minimum in a system of perfect, or ideal, conductors. It is analogous to Thomson's theorem on the equilibrium electric field and charge distribution in a system of conductors. We first prove Thomson's theorem using a variational principle. Our new theorem is then derived by similar methods. We find that magnetic energy is minimized when the current distribution is a surface current density with zero interior magnetic field; perfect conductors are perfectly diamagnetic. The results agree with currents in superconductors being confined near the surface. The theorem implies a generalized force that expels current and magnetic field from the interior of a conductor that loses its resistivity. Examples of solutions that obey the theorem are presented.

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Surface current density K: an introduction

Cited by 10 publications

References 3 publications

Simulating Surface Charge Dynamics

Simulating Surface Charge Dynamics

A Pressure Distribution Imaging Technique with a Conductive Membrane using Electrical Impedance Tomography

Magnetic Field and Current Are Zero Inside Ideal Conductors

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