Charged particle movement in arbitrary electromagnetic field

AI Thread Summary
The discussion centers on developing a simulation code for charged particles in an arbitrary electromagnetic field, specifically focusing on the motion of particles in a magnetic field without aligning the coordinate system. The user presents equations of motion for particle velocity components, indicating that constants determine the magnetic field's direction. They express uncertainty about how to proceed with their solution due to limited initial conditions for velocity components. A suggestion is made to use standard aligned equations along with a rotation matrix to address the arbitrary nature of the magnetic field. The conversation highlights the challenges of simulating charged particle dynamics in complex electromagnetic environments.
FlatronL1917
Messages
1
Reaction score
0
Hello there! This is my first post here, hopefully I am not posting in the wrong place.
Also, I am an engineer and have not used this stuff for years, so please be patient with me, I am pretty sure that my question is stupid :-)

I would like to develop a simulation code for charged particles moving in a electromagnetic field.
My thought is that, we may not always have the luxury to align the coordinate system to our magnetic field.
Assuming an arbitrary magnetic field vector B in every cell and ignoring the electric field for the moment, I tried solving the equations of motion to see if I can avoid discretization and got the following:

ux = c1x + (c2x+c3x)*cos(qB/m * t) + (c2x-c3x)*sin(qB/m * t)
uy = c1y + (c2y+c3y)*cos(qB/m * t) + (c2y-c3y)*sin(qB/m * t)
uz = c1z + (c2z+c3z)*cos(qB/m * t) + (c2z-c3z)*sin(qB/m * t)

It seems that the cij constants determine the direction of B. I only have the initial conditions for ux, uy, uz, obviously so I can not calculate them. Where do I go from this point? Is my solution wrong? Any help/pointer would be greatly appreciated.
 
Physics news on Phys.org
It looks like you plane on linear electric and magnetic fields, rather than "arbitrary" ones ... just with axis arbitrarily rotated.

In which case, all you need is the standard aligned equations and the rotation matrix.
 
This is from Griffiths' Electrodynamics, 3rd edition, page 352. I am trying to calculate the divergence of the Maxwell stress tensor. The tensor is given as ##T_{ij} =\epsilon_0 (E_iE_j-\frac 1 2 \delta_{ij} E^2)+\frac 1 {\mu_0}(B_iB_j-\frac 1 2 \delta_{ij} B^2)##. To make things easier, I just want to focus on the part with the electrical field, i.e. I want to find the divergence of ##E_{ij}=E_iE_j-\frac 1 2 \delta_{ij}E^2##. In matrix form, this tensor should look like this...
Thread 'Applying the Gauss (1835) formula for force between 2 parallel DC currents'
Please can anyone either:- (1) point me to a derivation of the perpendicular force (Fy) between two very long parallel wires carrying steady currents utilising the formula of Gauss for the force F along the line r between 2 charges? Or alternatively (2) point out where I have gone wrong in my method? I am having problems with calculating the direction and magnitude of the force as expected from modern (Biot-Savart-Maxwell-Lorentz) formula. Here is my method and results so far:- This...
Back
Top