Simulate the electromagnetic field generated by an alternating current

[njust-csc]

Hello, I've just started using the WarpX program recently. I want to use this program to simulate the electromagnetic field distribution generated by a 13.56 MHz sinusoidal current. How should I get started? It would be even better if I could simulate the electromagnetic field generated by this current flowing through a copper wire.

[ax3l]

Hi @njust-csc,

That is a great question and surprisingly, we have not have a mechanism for initializing a pure current field (but we do for E and B fields). For electromagnetic modeling, we could add something like this: https://warpx.readthedocs.io/en/latest/usage/parameters.html#external-fields Would that be sufficient for your use case?

But maybe a PIC code like WarpX is a bit of a heavy handed approach for the need and instead using an FEM code could be better to model the fields, e.g., MEEP?

What do you plan to do once the EM fields are modeled? Track relativistic particles with collective effects through them?

[njust-csc]

Thank you for your reply! I want to simulate the physical process of ICP. I need to simulate an induced electromagnetic field generated by the current in the coil. This electromagnetic field is coupled with the charged particles in the chamber, and this process is achieved by solving Maxwell's equations.

I have carefully examined the link you provided regarding external - fields. From a professional perspective, this approach appears to be more appropriate for the initialization of the electromagnetic field, rather than for its update at every time step. Additionally, the practice of updating the electromagnetic field through the reading of external files is likely to cause a substantial reduction in the calculation speed.

My present concept is to utilize the callback method to modify J within a specific region at every time step, thereby simulating the current in the coil. However, I am uncertain whether the J set in this manner will be incorporated into the FDTD calculation.

[njust-csc]

I found that directly modifying the value of J cannot activate the FDTD method, but directly modifying the value of E can activate the FDTD method. Is there any way to make the externally applied J also activate the FDTD method?