Nils Berglund | A slightly refracting magnetron-shaped resonator at higher wavelength @NilsBerglund | Uploaded August 2024 | Updated October 2024, 2 hours ago.
In this attempt to make my magnetron simulation more realistic by increasing the wavelength, I used excitations of lower frequency. I also made the anode slightly refracting, with a high damping coefficient. This is why some waves can be seen escaping from all sides. The reason for this choice is that I was afraid that perfectly reflecting boundary conditions would prevent the waves from entering the smaller cavities. Neumann boundary conditions would probably be more appropriate, but they are harder to simulate, and making the walls slightly refracting is an easier surrogate for that.
Magnetrons were used in early radars, and are still used in microwave ovens, as sources of the microwaves. Cavity magnetrons use a resonating cavity with several chambers, together with a magnetic field. In this simulation, there is no magnetic field, and waves are produced as pulses near the center of the device, so it does not represent a real magnetron. However, I still found it interesting to look at the effect of the resonating cavities on the output.
Since this simulation is in 2D, I added a channel at one side to act as an outlet for the waves. In 3D, my understanding is that the outlet would rather be along the axis of the device.
This video has two parts, showing the same evolution with two different color gradients:
Wave height: 0:00
Averaged wave energy: 2:11
In the first part, the color hue depends on the height of the wave. In the second part, it depends on the energy of the wave, averaged over a sliding time window.
There are absorbing boundary conditions on the borders of the simulated rectangle. The graph at the right shows a slightly time-averaged version of the signal.
Render time: 44 minutes 2 seconds
Compression: crf 23
Color scheme: Part 1 - Twilight by Bastian Bechtold
github.com/bastibe/twilight
Part 2 - Inferno by Nathaniel J. Smith and Stefan van der Walt
github.com/BIDS/colormap
Music: "Liberation" by Asher Fulero@AsherFulero
See also
https://images.math.cnrs.fr/des-ondes-dans-mon-billard-partie-i/ for more explanations (in French) on a few previous simulations of wave equations.
The simulation solves the wave equation by discretization. The algorithm is adapted from the paper hplgit.github.io/fdm-book/doc/pub/wave/pdf/wave-4print.pdf
C code: github.com/nilsberglund-orleans/YouTube-simulations
https://www.idpoisson.fr/berglund/software.html
Many thanks to Marco Mancini and Julian Kauth for helping me to accelerate my code!
#wave #resonator #magnetron
In this attempt to make my magnetron simulation more realistic by increasing the wavelength, I used excitations of lower frequency. I also made the anode slightly refracting, with a high damping coefficient. This is why some waves can be seen escaping from all sides. The reason for this choice is that I was afraid that perfectly reflecting boundary conditions would prevent the waves from entering the smaller cavities. Neumann boundary conditions would probably be more appropriate, but they are harder to simulate, and making the walls slightly refracting is an easier surrogate for that.
Magnetrons were used in early radars, and are still used in microwave ovens, as sources of the microwaves. Cavity magnetrons use a resonating cavity with several chambers, together with a magnetic field. In this simulation, there is no magnetic field, and waves are produced as pulses near the center of the device, so it does not represent a real magnetron. However, I still found it interesting to look at the effect of the resonating cavities on the output.
Since this simulation is in 2D, I added a channel at one side to act as an outlet for the waves. In 3D, my understanding is that the outlet would rather be along the axis of the device.
This video has two parts, showing the same evolution with two different color gradients:
Wave height: 0:00
Averaged wave energy: 2:11
In the first part, the color hue depends on the height of the wave. In the second part, it depends on the energy of the wave, averaged over a sliding time window.
There are absorbing boundary conditions on the borders of the simulated rectangle. The graph at the right shows a slightly time-averaged version of the signal.
Render time: 44 minutes 2 seconds
Compression: crf 23
Color scheme: Part 1 - Twilight by Bastian Bechtold
github.com/bastibe/twilight
Part 2 - Inferno by Nathaniel J. Smith and Stefan van der Walt
github.com/BIDS/colormap
Music: "Liberation" by Asher Fulero@AsherFulero
See also
https://images.math.cnrs.fr/des-ondes-dans-mon-billard-partie-i/ for more explanations (in French) on a few previous simulations of wave equations.
The simulation solves the wave equation by discretization. The algorithm is adapted from the paper hplgit.github.io/fdm-book/doc/pub/wave/pdf/wave-4print.pdf
C code: github.com/nilsberglund-orleans/YouTube-simulations
https://www.idpoisson.fr/berglund/software.html
Many thanks to Marco Mancini and Julian Kauth for helping me to accelerate my code!
#wave #resonator #magnetron
