In this space, visitors are invited to post any comments, questions, or skeptical observations about Philo T. Farnsworth's contributions to the field of Nuclear Fusion research.
Subject: Re: Another 2 cents on microwaves
Date: Aug 16, 7:06 pm
Poster: Jim Lux
On Aug 16, 7:06 pm, Jim Lux wrote:
>However, there is a low voltage low output device that might have some interesting features for an add-on to the fusor. This would be the Gunn diode. Check out: http://www.mdtcorp.com/gunndiod.html for some technical info.
It would be the rare Gunn diode that is cheap and puts out more than a 100 mW, and I don't know that power that low would make any difference. As for combining the outputs, it would be a significant technical challenge, because you have to get the phases the same, a VERY non-trivial task with Gunn Oscillators. And, even then, the power would add only at a few points, depending on the geometry.
If you want to use microwave power, use cheap, readily available microwave oven magnetrons (>1kW for <$100). Just know what you are doing before you cook yourself.
a higher frequency (around 10 GHz) so the ouput should couple more efficiently to the fusor plasma and are simple enough to be powered directly by $2 "block" wall transformer if you wanted to go real cheap.
Determining how to couple the power into the plasma is a bit tricky, since the plasma is a conductor, and reflects a fair amount of the incident power. A suitable cavity will reflect it back to the plasma, but, I suspect that the challenges in this would far outweigh any advantages.
>Downsides involve machining and sealing several holes into your vacuum chamber. Fortunately the wavelength in question is small enough so that waveguides would probably be superfluous.
It's worse, the wavelength is small (3 cm for 10 GHz), so propagation in your chamber (which is many wavelengths in size) will be hard to predict, unless you have a good (read high $$) simulation program. It is much easier to design a single mode cavity when most of the cavity dimensions are on the order of or smaller than a wavelength. (say, 2.45 GHz == 12 cm)
- Re: Another 2 cents on microwaves - Jones Beene Aug 16, 10:03 pm