High level FDTD question

[dom11990]

I noticed that the energy during a simulation seems to fluctuate up and down. Could you explain what this value represents? If it is the remaining energy in the simulation box, shouldn't it be monotonically decreasing once the excitation signal is done?

thanks!
dom

[thorsten]

Hi Dom,

I'm sure I have answered this before but I cannot find it

The displayed energy is only a rough/fast estimate. It for example completely neglects the material distribution (aka assumes everything to be vacuum or metal).

During the excitation the energy in-flow is not constant and some decay/loss may already occur. Thus and up and down is to be expected and normal.
After the excitation is done, the energy should indeed only go down but if energy leaves or enters dielectrics the energy estimation may over- or underestimate the correct value and thus may increase again. But this effect should only be small.

I hope that answers your question?

regards
Thorsten

[dom11990]

Yes it does, thanks