Could a Farnswirth fusor (the origanal type) work with higher voltage?

[Earl of Plasma]

What I understand the Farnsworth Fusor did not have a physical inner cage or any kind of material center, source The farnsworth chronicles I don’t know how much I can trust this source. It’s seem to be very pro Farnsworh the person. But it’s interesting and he was a great inventor and engineer.
It’s now doubt the device produce fusion and confined plasma well. Many claims that the device was never near producing more energy than consumed, and that it never can. That’s because you can’t get high enough ion concentration, which is due to that ions repel each other when they come to near. So the reaction will not be intense enough to begin with. According to the criticism.

What happened if you rise the voltage, the potential of the outside shell. Could you rise the ion concentration then? Maybe you should do the device bigger. The original device was just like a football. I suppose a bigger device reduce losses from surface compered to the increased volume. Could that possible lead to a self sustaining process? According to the article, they got more and more neutrons the higher the voltage. They tried up to 150 kV at least. That would get a temperature of more than 1 billion Kelvin. But I suppose that it also confine the plasma harder, because the potential of the shell is the confinement. The article says that, at the end of the project, they could switch of the current and the fusion went on for almost 30 sec.

I can’t forget to mention the polywell, but I can’t see why it would work any better. The confinement seem to be much less reliable then the electrostatic shell of the Farnsworh fusor. It is said to have a virtual negative dwell, not exposing any material for hot plasma, but so does the original Farnswirth fusor (not the simplified ones amateur often builds, which have a metal cage as negative dwell)

The article says that the company Farnswarth worked for ITT, assigned all the patents and gradually layoff the project, but that’s just what they said. I don’t know if that’s true or not.

[delt0r]

Beam fusion, which what the Farnsworth is, can’t get around the simple fact that your more likely to bounce of other ions rather than fuse. Many many times more likely. This is the so called star mode, and I have not read any credible reports on anything working after power down, that is not even consistent with its claimed working principals.

Non neutral plasma has a well defined potential you need for confinement. Its scales with the amount of charge enclosed and the surface area. Even the size of the moon is not enough for any reasonable fusion rate.

[Earl of Plasma]

Non neutral plasma has a well defined potential you need for confinement. Its scales with the amount of charge enclosed and the surface area. Even the size of the moon is not enough for any reasonable fusion rate.

What exactly do you mean by that?

Non neutral plasma has a well defined potential you need for confinement.

Should that mean that’s quite easy to confine the plasma? Easy with an electrostatic confinement? It can mean a lot of things. I suppose positive ions bounce back harder the higher voltage the shell has. That would lead to better confinement, shouldn’t it? Better confinement lead to higher ion concentration and therefor more reactions per volume.

I’ve read about the very simple amateur fusors, and they can never get enough fusion reactions. Is it they you refer to? They also have a metal cage at the center that steal a lot energy when fusion intensity get higher. The fusor Farnsworth made was much better, that’s for sure and had no metal cage.

[delt0r]

Well you could learn some electrostatics yourself you know. Its not that hard and any stage one uni book or higher level school text book would have everything you need to know. Both about fusion and cross sections and electrostatics. There are some free ones online these days as well.

|But sigh. Understanding and learning the problems is something so many people just don’t want to do. They have all these “good ideas” as if no one else has thought of them.

Long story short non neutral plasma means there are (in this case) more ions than electrons, and they repel each other. The net charge enclosed in a sphere gives you the electric field at that surface, and ions will be forced out of the sphere by that electric field. To “heat” ions and propel them into this sphere would need at less this much electric potential. You calculate that potential using Gaussian surface. That is left as an exercise for the reader.

You could add more electrons. But then the ions hit the electrons and convert all that energy into xrays, cooling the plasma. Even with no electrons it still doesn’t work. Quite simply you scatter off the ion far more often than you fuse. As a result the ions quickly thermalize and your back to Lawson criteria.

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