Thanks Ardavan for your suggestion. So it means that I can simulate nonpropagating waves only using a ContinuousSource? I can try that. In my previous test, the simulation stopped when I had a narrow bandwidth Gaussian source containing only nonpropagating frequencies, complaining about the NaN and Inf so I thought I was not allowed to simulate only evanescent waves but maybe I was wrong.
On Sun, Dec 6, 2020 at 11:51 PM Ardavan Oskooi <ardavan.osk...@gmail.com> wrote: > If you want to investigate the field profile, it is better to use a > ContinuousSource rather than a GaussianSource and time step for a > sufficiently long time until the fields have reached steady state. The > advantage of this approach is that you can see what is happening at a > single frequency (comparing e.g. evanescent and non-evanescent waves) > rather than over some bandwidth which is difficult to interpret. Note > that you can take a snapshot of the fields at the end of the run using > the plot2D routine. > > On 12/6/20 19:18, Mandy Xia wrote: > > To simplify the problem, I tried to record the incident field only, > > without introducing the scatterer. Here are a few animations. In all > > three tests, I have a 3D simulation where the z direction has a > > periodic boundary condition and boundary layers in the x y directions > > and I show the y=center slice over time. In the first simulation, I > > have pml boundary layers and simulate a source that contains only > > frequencies with well defined mapped incident directions; the second > > simulation also has pml boundary layers but the source is defined such > > that it covers a larger range of frequencies and some small > > frequencies don't have well-defined incident angles; the third > > simulation has thick absorber boundary layers and the source is > > defined the same as in the second simulation. I observed that only in > > the first simulation the incident field looks like it is > > propagating in a fixed direction whereas the other two do not. I was > > wondering if this is what I should expect when there are evanescent > > waves and whether this could be the source of the error in my > > scattering tests. >
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