X axis for Fourier Transform

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So I am doing a RF simulation in the frequency domain. I want to look at the beam profile behind my launch port as there is a back scattering event happening.

I was dealing with other scattering events possibly interfering with my data so I though I could do a spatial fourier transform and filter out the other scattered waves by their wavenumber

My main question is the x axis data for my line graph showing the FFT, should i just make it the dataset space variable or should i have it as arc length to properly display the intensity vs wavenumber. The hierarchy of data is as follows I have a cut line 2d that samples the data directly behind my launch port I then have a spatial FFT that has its dataset from the cut line 2d

I then create a line graph from the spatial FFT with the following expression for Y

abs(fft(sqrt( (0.5real( emw.Exconj(emw.Hy) - emw.Eyconj(emw.Hx) ))^2 + (0.5real( emw.Eyconj(emw.Hz) - emw.Ezconj(emw.Hy) ))^2 + (0.5real( emw.Ezconj(emw.Hx) - emw.Ex*conj(emw.Hz) ))^2 )))

Im confused on this because the peak K when i have the x axis as dataset space variable is rather low

meanwhile if I choose arc length I get this where the peak is rather high compared to my vacuum wavenumber of my wave of 1467 1/m

I have attached the link to my mph file and the interpolation file used for my plasma data if that is of interest.

https://drive.google.com/drive/folders/19PSXzqse9gKx34wrRkHaxVEES8iZuziW?usp=sharing


1 Reply Last Post Jul 27, 2025, 12:44 a.m. EDT

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Posted: 7 hours ago Jul 27, 2025, 12:44 a.m. EDT

Sorry I fixed this it was an error on my part

Sorry I fixed this it was an error on my part

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