Total energy (EM field + particles) is not conserved but increasing

[deSUBHAM]

energy_conversion_diff_energy_force_free_theta_point05.pdf
Hi,

I have a input file for magnetic reconnection but with plasma beta is greater than 1. When I plot the evolution of different energies, I find that the all the energies (magnetic, electric and particles) are increasing after some time, which does not make sense because during magnetic reconnection particles' gain energy from the magnetic field. As a result of this, the total energy (EM field + particles) does not remain constant with time as you can see in the attached picture. My question is how can the total energy increase? It might decrease if there is heating by any means. This is a bit confusing to me. I would appreciate any clarification.

Thanks.

[ax3l]

Hi @deSUBHAM,

Thank you for the report.
We really need to see an input file to understand what is going on here: solvers used, boundaries, etc. Did you already do a convergence scan (in resolution)?

[deSUBHAM]

Hi @ax3l,

Thank you very much for your reply.
Please find the corresponding input file attached here. I did not do the convergence test yet though.
input_2d.txt

[ax3l]

Thanks! Looks like this is an EM simulation with periodic + pec field and periodic + reflecting particle bounds.

The CFL is resolved, but I would still recommend to first to a convergence test, ensuring your plasma frequency is well resolved.

We are working on a few subtle improvements for boundaries to improve energy conservation, i.e., #5650 for PEC, but the amount you are describing sounds like your problem might be under resolved.

Let us know if this helps and if the situation improves with better resolution.

[deSUBHAM]

Hi @ax3l,

Thank you for your reply. The error in the conservation of energy was due to not resolving the Debye length. Now as I am resolving the Debye length, there is no such issue.