Questions tagged [electromagnetism]

For questions about modeling phenomena related to electromagnetic fields.

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A Question About a Claim from 1991 Computational EM paper about the Cancellation of certain Boundary Terms

Please let me know if this is not the appropriate site for this question. I found questions regarding EFIE/MFIE/CFIE on this site, so I thought my question might fit. I am studying the paper by Putnam ...
o0BlueBeast0o's user avatar
6 votes
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953 views

Understanding Boundary Condition in FEM

I am trying to understand Dirichlet and Neumann boundary conditions in FEM and I wanted to know if my inference is correct. To articulate my understanding, lets consider a simple case of TE and TM ...
Aakusti's user avatar
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4 votes
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307 views

How can I solve the wave equation for a circular rod in cylindrical coordinates using finite differences?

I have a problem with the stability of finite difference method for the wave equation in cylindrical coordinates. the equation is: $$ \frac{\partial^2 \omega_n}{\partial r^2}+\frac{1}{r}\frac{\...
alireza's user avatar
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3 votes
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Spectral solver on em-pic

I'm recently studying for the spectral solver to implement EM-PIC code. I read an article and have some questions. Many PIC codes uses spectral solver to overcome numerical artifacts on FDTD. In the ...
asdgaaa1123's user avatar
3 votes
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135 views

Finite difference method for coupled PDEs: optimizing performance (time step, iterations per step)

I'm solving coupled PDEs using finite difference method: Incompressible Navier-Stokes and the divergence-free induction equation (Maxwell's equations) with non-uniform electrical conductivity. The ...
Charles's user avatar
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2 votes
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Numerical integration in Fourier space over 3D grid

I am attempting to implement a model outlined in this paper: General magnetostatic shape–shape interactions Background This model allows the calculation of magnetostatic interaction energies between ...
JasonC's user avatar
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2 votes
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48 views

In electromagnetic simulation, how much does the feed model impact an antenna's directivity performance and E-field phase readings?

Question: How much would a simplified feed model in an EM simulation alter an antenna's directivity and the E-field phase reading when compared to using a more complicated/realistic feed model? I am ...
Xingda Chen's user avatar
2 votes
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62 views

Symplectic (or alike) integrator for system with Coulomb singularity and time-dependent potentials

I am trying to calculate classical trajectories for a single positive ion and a single electron inside an RF trap. Therefore, I am dealing with a two-body system that possesses: Coulomb potential ...
michalt's user avatar
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378 views

Numerical simulation of magnetic dipole in a inhomogeneous magnetic field

Goal: I want to use Python to illustrate how a magnetic dipole with magnetic moment m2 moves in a non-homogeneous magnetic field in a 2D-Plane. This field is generated by another magnetic dipole with ...
tester931's user avatar
2 votes
0 answers
47 views

Open source multiphysics software that can model the interaction of two insulators with a user-specified electrical force law?

Given two solid bodies of masses $m_1$ and $m_2$ with invariable charge distributions $\rho_1(\mathbf{r_1})$ and $\rho_2(\mathbf{r_2})$ in them,* respectively, I would like to model the electrical ...
Geremia's user avatar
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2 votes
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Solving electrostatics Poisson equation with Intel MKL routines

I am trying to solve the 3D Poisson equation $$\nabla\cdot(\epsilon(\mathbf{r})\nabla) u(\mathbf{r}) = f(\mathbf{r})$$ I notice intel advertises routines that appear to solve $$\nabla^2u(\mathbf{r}...
DJames's user avatar
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COMSOL - Implementing Perfectly Matched Layers (3D)

If there are any COMSOL gurus here, I want to simulate a 3D RF system infinite in 1 direction. I realize I need to use PML's, but am unsure how to configure them. it seems that simply scaling them by ...
Hopeful's user avatar
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1 vote
0 answers
42 views

Spectral Intensity of complex signal

I'm simulating an electromagnetic wave that has a real and imaginary part. Something like: $$ E(x,t) = A(x,t) e^{-i(\omega t - k x)} $$ Where $A(x,t)$ is some complex amplitude. Then taking the ...
Ebar's user avatar
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Stress and periodic boundary conditions

In the textbook definition of the stress tensor it is defined at each point in space and therefore position dependant. When three dimensional periodic boundary conditions are used, I have seen it ...
nameiki's user avatar
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How can the current-voltage relationship of a series of tunneling junctions be most easily computed?

I'm working on a research project with my professor where we're trying to figure out how to determine the necessary semiconductor composition for a solar cell to have a particular bandgap in order to ...
Mikayla Eckel Cifrese's user avatar
1 vote
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201 views

Magnetic field simulation for "quasi-solenoid" - Where to start?

I would kindly ask you which (preferably free) programs / codes do you suggest for the numerical simulation of the problem described below. I am not asking for the full solution, but just want to ...
t387's user avatar
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Can I build an electrostatic simulation of conductive objects using just the method of images?

I wish to build a simulation of self-assembling wires. Think lots of ball bearings in a 20KV electric field and they form emergent structures. If I use the method of images to figure out what the ...
Mandrake_The_Magician's user avatar
1 vote
0 answers
43 views

Digital beamforming: how payload manipulation can change beam direction without manipulating the carrier?

I'm interested in how digital beamforming works and I can not find an answer for a lot of time. I googled, asked teammates, and couldn't get it. Let me describe my question. From my understanding, the ...
Petr Kirilenko's user avatar
1 vote
0 answers
56 views

Results blow up when number of intervals is increases (Yee algorithm FDTD, dielectric sphere)

I have been trying to write a program that analyses EM wave scattering by a dielectric sphere for a project. The reference is Sadiku's book Numerical Methods in electromagnetics Edition 3. Now the ...
Hridey's user avatar
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1 vote
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How can I improve the accuracy of the calculation of the magnetic field in Gmsh/GetDP?

I need to calculate the magnetic field along a straight line in proximity of an array of 6 magnets. I used the tutorial files "magnets" included in Gmsh and I slightly modified the file in ...
sintetico's user avatar
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1 vote
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432 views

More efficient way to calculate magnetic field using Biot-Savart

I am writing a program in python that is supposed to calculate the magnetic field along a conducting coil that is made up of a bunch of points, and the magnetic field is generated by other conducting ...
Mikeb's user avatar
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1 vote
0 answers
46 views

Multipole expansion for magneticfield intesity (magnetization)

I'm using the Barnes Hut method to calculate the magnetic vector potential induced by an applied current. Given as: $\begin{equation} A(r) = \frac{\mu_0}{4\pi} \int_V\frac{\bf{J(r')}}{|r-r'|}dV(r') \...
Noveel's user avatar
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1 vote
0 answers
77 views

Magnetostatic modelling Radia: Increasing distance between magnets a produces positive force until a certain point, beyond which force goes haywire

I have two sets of magnets. One set consists of two electromagnets (Shown below: Blue) and the other set consists of two NdFeB N40 permanent magnets. Both sets of magnets lie on the same plane. I want ...
James O'Farrell's user avatar
1 vote
0 answers
120 views

Band structure of nonlinear Schrodinger equation with one dimensional potential

I have a nonlinear Schrodinger equation which reads: $$ \frac{1}{2} \frac{d^2u}{dx^2}+ |u|^2u + V(x)u = -i \frac{du}{dz},$$ where $V(x)=\cos(wx)+ i a \sin(wx)$ and $w$, $a$ are numbers. How to ...
foi's user avatar
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1 vote
0 answers
80 views

Numerical scheme to solve Maxwell equations with fixed potential boundaries?

We have a 2D electromagnetic field (in the sense that: $E=(E_x,E_y,0)$, $B=(0,0,B_z)$, and all derivatives with respect to $z$ are $0$), and we are considering a system made up of two walls at $x=-b$ ...
Ben Stokes's user avatar
1 vote
0 answers
83 views

Can x-ray back-projection be converted to hard-field magnetic induction tomography?

This is a question about hard-field back-projection as used in x-ray tomography, applied magnetic induction tomography. Al-Zeibak and Saunders have shown that x-ray filtered backprojection can be ...
Brendan Darrer's user avatar
1 vote
0 answers
75 views

Dielectric in an external electric field

I want to numerically solve for electric field of an object in an external electric field. The object has linear displacement field such that its permitivity ($\epsilon$) is constant. The object's ...
heaven-of-intensity's user avatar
1 vote
0 answers
101 views

Representing a 3D system in 2D (Electromagnetic modelling)

Ok so I'm a complete beginner in computational modelling (I use analytical methods of physics typically) but I would like to model an anisotropic, aperiodic (but not random) finite array of metallic ...
Tom's user avatar
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1 vote
0 answers
91 views

Calculating tangential electric field intensity on the boundary

I have an object with surface charge $\sigma$ for which I want to caclulate tangential electric field which would correspond to mathematical formulation: $$ \vec{E}(\vec{x}) = \nabla_x \int \frac{\...
Jānis Erdmanis's user avatar
1 vote
0 answers
365 views

How to solve a nonlinear diffusion equation?

Consider a thin film with a perpendicular applied magnetic field $H_a$ in $z$-axis. The nonlocal relation between $H_a$, the self-field $H_\text{self}$ (generated by the eddy current $J$) and the ...
Obaid's user avatar
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0 votes
0 answers
46 views

Calculating a 2D Ewald sum for a multipolar expansion

I am attempting to calculate the potential of a particle at the center of an infinite two-dimensional lattice as per the following reference: Reference: Lambin, PH & Senet, P. Ewald Summation of ...
JasonC's user avatar
  • 33
0 votes
0 answers
30 views

Problems performing 1D-FDTD for dispersive dielectric uisng lorentz model in Julia

So I am trying to model a dispersive dielectric using the Lorentz model in Julia, more specifically I am trying to obtain the frequency-dependent reflectivity of the material. I am ultimately trying ...
Emre Durmus's user avatar
0 votes
0 answers
164 views

Finite difference solver for the 2D Poisson's equation with an integral boundary condition

I wanted to attempt an implementation of a finite-difference-based solver for the 2D elctrostatic Poisson equation when metallic objects are present. Also, I hope to take as input, the location of ...
Siddharth Ambekar's user avatar
0 votes
0 answers
196 views

2D axisymmetric Magnetostatics Finite Element Method solver

I am new to the field of magnetostatics. I wish to write a 2D finite element code for obtaining the magnetic field inside a solenoid coil. I have started with a 2D code and have followed the method as ...
Shekhar's user avatar
0 votes
0 answers
120 views

Plotting the motion of a positive charge in a cylindrically symmetric magnetic field

I want to plot the motion of a positive charge in a cylindrically symmetric magnetic field. I am assuming a cylinder around the z-axis, with the magnetic field going in clockwise direction. The B-...
August Jelemson's user avatar
0 votes
0 answers
267 views

FEM port Boundary definition for electromagnetics and wave guides

We are currently in the process of implementing ports in our EM FEM simulation SW. We have come across the definition of boundary conditions for the ports, and we do not understand the equation for ...
bbch's user avatar
  • 33
0 votes
0 answers
43 views

Calculating magnetic flux density

I have a geometry where current density distribution is constant. I can calculate the $z$ component of magnetic flux density according to Biot-Savart law as following: $$B_z(x,y,z) = \int\limits_x\int\...
strahd's user avatar
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0 votes
0 answers
204 views

How to use FEniCS to calculate the electric field of an isolated charged sphere

Initially I thought that this is the kind of question which ought to have already been answered in the form of an example online, but so far I haven't found one. I will admit that I am very new to ...
John Tiessen's user avatar
0 votes
0 answers
83 views

How to calculate the interior value of triangular element in edge (vector) finite element?

I was using an edge (vector) finite element to solve electromagnetic diffusion (two-dimensional cases). The element that I used was a triangular element. I have got the result of the finite element in ...
yihaa's user avatar
  • 9
0 votes
0 answers
79 views

Numerical scheme to calculate the normal mode of a set of hyperbolic PDEs?

I would like to solve the linearised, ideal, MHD equations, where the gas pressure is zero. $$\frac{\partial u_x}{\partial t}=v_A^2(x,z)\left[\nabla_{||}b_x - \frac{\partial b_{||}}{\partial x}\right],...
Peanutlex's user avatar
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0 votes
0 answers
294 views

COMSOL Circularl polarization

I'm having some problems trying to implement circularly polarized light in COMSOL Muliphysics. For a isotropic homogenous media, I've obtained without problems the TE and TM reflectance curves. ...
Antonio Ganfornina Andrades's user avatar
0 votes
0 answers
124 views

Discretisation by FVM with triangulare mesh

I work on electromagnetic modeling, and I use the finite volume method as a tool, so I want to develop code by the modified finite volume method (with triangular mesh), my problem studied is in a ...
Ali Hammouche's user avatar
0 votes
0 answers
678 views

Parallel plate capacitor as simple superposition of Coulomb-fields

I am trying to calculate and visualize the electric field inside and outside of a parallel plate capacitor by assuming a uniform distribution of point charges on each plate and by adding up the ...
dp21's user avatar
  • 11
0 votes
0 answers
182 views

FEniCS implementation of Maxwell equations for a dipole antenna

someone knows where I can find a FEniCS implementation of Maxwell equations for a dipole or other type of antenna? I mean a dipole antenna with an arbitrary geometry of every 'leg' in the dipole.
S. Feunmajer's user avatar
-1 votes
1 answer
91 views

Meep C++ interface benchmark

I am having trouble getting a good parallelization with FDTD simulations in Meep. Originally, I tried to use the Python interface on a rather big computing cluster, but the runtime of my simulations ...
Daniel R's user avatar
-1 votes
1 answer
101 views

Simulating magnetic particles in a field free point generated by two opposing magnets

This is probably a long shot with such a short time, but I've been trying to get theoretical data for a project I'm working on. The project involves using a very simplified version of magnetic ...
sgehugh2's user avatar