Questions tagged [electromagnetism]

For questions about modeling phenomena related to electromagnetic fields.

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How to Implement Analytical Magnetic Field Equations into a Physics-Informed Neural Network (PINN) in PyTorch?

I'm working on a project that involves modeling the magnetic field around Europa, one of Jupiter's moons, using a Physics-Informed Neural Network (PINN) in PyTorch. My goal is to implement analytical ...
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 ...
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 ...
2 votes
0 answers
79 views

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 ...
4 votes
1 answer
662 views

Is my differential equation solving code wrong?

I am trying to simulate LLG equation without damping. The equation is $$\frac{d\vec{m}}{dt} = \vec{m}\times\vec{H}$$ I am solving in spherical coordinates as LLG equation is known to have problems in ...
2 votes
0 answers
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 ...
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 ...
1 vote
1 answer
293 views

Euler's Method for fast moving particle trajectory

I'm trying to figure out how a magnet affects the trajectory of a particle travelling near the speed of light downwards toward the ground. The equation for the force of the magnetic field is pretty ...
1 vote
0 answers
41 views

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 ...
1 vote
0 answers
30 views

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 ...
0 votes
1 answer
172 views

Modeling ferromagnetic materials in a primitive python FEA

I am working on a primitive 2D DIY magnetic "FEA" solver for a class project. It's really just a big NumPy array where each element in the array can be one of the following: Air Current ...
2 votes
0 answers
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 ...
3 votes
1 answer
223 views

Average value divergence in spectral method for Poisson equation

I'd like to know how to deal with a divergence when trying to solve the Poisson equation for electrostatics with a simple spectral method. I'm not sure how to best state my problem, so I'll explain ...
1 vote
0 answers
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 ...
-1 votes
1 answer
84 views

Billiard reflection inside a triangular mesh

I am currently interested in billiards and their trajectories. I would like to simulate a billiard inside a water-tight mesh. A mesh basically consists of a list of points in 3D space (vectors with 3 ...
3 votes
3 answers
2k views

Scalar vs. vector potential for magnetostatics

When trying to solve a magneto-static boundary-value problem (BVP) ($\nabla \times \mathbf{H} = \mathbf{J}$ and $\nabla \cdot \mathbf{B} = 0$), one can use either the magnetic vector potential $\...
1 vote
1 answer
414 views

Integral of the Poisson Kernel

I am trying to solve the following integral: $$ I (r,\theta) = \frac{1}{2\pi}\int_0^{2\pi}\frac{f(\phi)(1-r^2)}{1+r^2-2r \cos(\theta-\phi)}d\phi$$ where $0\le r<1$ and, $$f(0\le\phi<\pi/2) = +\...
-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 ...
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 ...
1 vote
0 answers
37 views

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 ...
1 vote
1 answer
815 views

Simple particle-in-cell examples

I am studying about the 1D EM-PIC (Electro Magnetics using particle-in-cell) simulation. I want to have a simultaneous time-integration of the electric/magnetic fields plus the motion of free charges ...
2 votes
1 answer
92 views

Is there any method to incorporate minor changes into solved meshes to speed convergence in particle-in-cell solvers?

I'm trying to perform a $10^6$ timestep electrostatic particle-in-cell simulation on a rather large mesh, with very limited computational resources (a single GPU). Because of the large number of ...
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 ...
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 ...
3 votes
2 answers
1k views

Minimum number of elements (mesh size) for electromagnetic simulation

Does someone have a reference for the minimum number of elements (or maximum mesh size) for electromagnetic simulations where a mathematical or numerical explanation is given? I have found several ...
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-...
0 votes
1 answer
115 views

How to Calculate magnetic and electric field in 2D Magnetotelluric using Edge based Finite Element

I calculate 2D Model of Magnetotelluric responses which are apparent resistivity and phase. I do the calculation for Transverse Electric (TE) mode. Then I used edge based finite element with ...
-1 votes
1 answer
634 views

Using ODE to plot particle-motion with scipy.integrate.solve_ivp

My Problem: A positively charged particle (mass = 2 * 10-27 kg) is moving along the x-axis. It is travelling in a homogenous magnetic field such that the field axis in z-direction. The energy of the ...
4 votes
1 answer
567 views

Weak Formulation of Poisson's Equation for Electrostatics with Surface Charge

I am currently attempting to use FEnICS to solve an electrostatic problem with two materials of different permittivity $\varepsilon_1$ and $\varepsilon_2$ forming an interface: Consider a domain $\...
5 votes
2 answers
256 views

How to create a good preconditioner for a system of linear equations that is created with FEM applied on the time harming Maxwell eqution?

I set out to solve the time harmonic Maxwell equation numerically which was discritzed using FEM and with the use of Nedelec elements as basis and test functions. The equation reads: $$ \nabla \times \...
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 ...
3 votes
1 answer
309 views

Finite element method for high-frequency electromagnetics

I am writing a project about the Finite element method for use in high-frequency solutions of Maxwell's equations. This could be for use in antenna design and similar. I have some trouble ...
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 ...
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\...
1 vote
1 answer
230 views

Electrostatic Force - Simulate Trajectory of Test Particle using Runge Kutta - Force always Repels

In the center of a 2D-Plane a positive static charge Q is placed with position r_prime. This charge creates a static electrical Field E. Now i want to place a test particle with charge Q and position ...
2 votes
0 answers
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 ...
-1 votes
1 answer
160 views

plotting $F=K \frac{q_1 q_2}{r^3}$ in python

I tryin to plot the position of electron in the hidrogen atom by Coulomb's law, $F=K \frac{q_1 q_2}{r^3}$ This is mi code ...
6 votes
0 answers
109 views

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 ...
2 votes
1 answer
514 views

Help with modified bessel functions

I'm trying to parse the following expression (Eq. 35 in The Magnetic Field in the Vicinity of Parallel and Twisted Three-Wire Cable Carrying Balanced Three-Phased Current) in Python and calculate its ...
1 vote
0 answers
105 views

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 ...
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 ...
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 ...
1 vote
0 answers
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 ...
4 votes
2 answers
2k views

Data analysis of a magnetic hysteresis loop

I am a physics undergrad and I have MOKE data for a magnetic material (thin permalloy film on a silicon substrate). Here is one of the hysteresis loops I obtained, plotted using Python: The form of ...
1 vote
1 answer
120 views

Simple reference problems for time harmonic Maxwell equations

For Navier-Stokes problems we can often choose a relatively simple verification problem such as the lid driven cavity, flow over a cylinder, or flow over a backward facing step to verify our ...
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],...
4 votes
1 answer
4k views

Finite difference methods in cylindrical and spherical co-ordinate systems

I am quite familiar with finite difference schemes in cartesian coordinates. The key point here is that every point in the cartesian grid is treated equally as the spacing between consecutive points ...
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. ...
4 votes
2 answers
2k views

Kronecker product representation of the finite difference laplacian

The laplacian equation when discretized gives a system of linear equations that can then be solved. See the answer to this question: https://math.stackexchange.com/questions/3120948/discretization-...
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 ...