starts with vacuum theroy, am i looking at it wrong, or just a unique veiw.

It may be difficult to separate "theory" from "application," but let''s see if this helps facilitate the discussion.
electron
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starts with vacuum theroy, am i looking at it wrong, or just a unique veiw.

Post by electron » Mon Jan 07, 2013 11:10 pm

Hey everyone,

First off I want to admit I'm not huge on reading. However I have read most of the frequently asked questions and although I may have missed the answer, I still seem to be visualizing and thinking that
The vacuum ..

Shouldn't be so important , until after all the deuterium electrons are no longer a problem and the protons are held in the absolute centre. Only after the protons have produced a mass bigger then the inner grid.

Should we need to crank up the vacuum to original space vacuum?


Also why deuterium, sorry but I do not see a deuterium sun. I do see a hydrogen sun with the promise of the photoelectric effect.

Please don't tell me I need to move to another forum. It's hard when you spend your entire life pulling things apart.

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Re: starts with vacuum theroy, am i looking at it wrong, or just a unique veiw.

Post by Carl Willis » Mon Jan 07, 2013 11:24 pm

A low pressure (vacuum) is needed in the Farnsworth Fusor in order that the nuclei destined for fusion will reach high velocities before colliding. The distance the particles can travel between collisions is characterized by the mean free path between collisions, depending on pressure, temperature, and gas species. In typical fusors, it is on the order of centimeters. In high pressure conditions (like atmospheric pressure) the accelerating voltage cannot be maintained across dimensions small enough that the ions could accelerate significantly--you would just get an arc discharge. On the other extreme, a vacuum like that in outer space has generally not a single atom in a volume the size of a typical fusor. Clearly you need to have a usable supply of atoms to fuse.

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Re: starts with vacuum theroy, am i looking at it wrong, or just a unique veiw.

Post by Dan Tibbets » Tue Jan 08, 2013 2:50 am

Your consideration of the protons being a mass in the center of the fusors makes me think you are thinking along the lines of gravity, with fusion being an 'event horizon' type threshold. If, so , your concept is completely wrong. Fusion is all about two nuclei hitting with enough speed and on target to such an extent, that the electromagnetic repulsion is overcome and the stronger but much shorter range strong force can fuse them together, with the release of kinetic energy in many situations where the nuclei are lighter than iron. Pressure or density does not effect this in normal conditions, except that with higher densities the chances of these head on collisions occurring goes up. There are all sorts of complications, but that is the basic idea.

As for Deuterium fusion, it also occurs in stars, or at least protostars. D-D fusion is much easier than proton- proton fusion. When a star forms, deuteriun fusion starts up well before hydrogen fusion (hydrogen = proton), and proceeds much faster (by a factor of up to ~ a billion trillion times). Even though the deuterium in the gas of the young star is only ~ 1/6,000th that of the hydrogen, it burns up very quickly (perhaps a few thousand years) and is only a blip on the protostars condensation towards main sequence hydrogen burning. The same occurs with several other light elements in the stellar nebula, like several isotopes of lithium.
In very small stars fusion tends to proceed much more slowly, and in the tiniest stars or Brown Dwarfs, the deuteriun and lithium burning may last billions or even 100s of billions of years, and hydrogen burning may be essentially non existent. It is all dependent on the density/ concentration of the various fuels and the heat they produce which stabilizes the star against further gravitational collapse. The gravitational collapse provides the initial heat that leads to fusion, while the fusion keeps the gas hot enough that the gas pressure prevents further gravitational collapse. In a fusor the gravitation effects of the gas is so ridiculously small that it is completely irrelevant.

Along with the density and temperature, the likelyhood of the reaction is represented by the fusion cross section curve for the reaction. Deuterium - tritium is about 100 times easier than D-D fusion, that is why it is used in the relatively low temperature Tokamaks. Fusors have no problem fusing D-D, at least at interesting tiny quantities. Deuterium- helium3 or He3-He3 can also be used but it is more challenging. Even hydrogen Boron (P-B11) can be done with increasing difficulty. But all of these are ~10^20 times easier to fuse than hydrogen. The very best Fusor might succeed in fusing two hydrogen once every trillion years or so- not very entertaining.
Stars can fuse hydrogen in significant amounts despite the dismal cross sections because their cores are extremely dense and stupendously large. And they have stupendous amounts of mass that does result in a lot of gravity. This gravity provides the original heat and the confinement of the gas, but it is not directly driving the fusion. Things change when the gravity becomes even greater or the fusion peters out, but that is a whole different set of books. If you wonder why gravitational collapse generates heat, consider the Gas laws, or why compreeing air causes it to heat up.


Fusion rate is basically determined by the Fusion Cross Section * temperature *density squared * volume.

Dan Tibbets

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Re: starts with vacuum theroy, am i looking at it wrong, or just a unique veiw.

Post by electron » Tue Jan 08, 2013 6:02 am

Thanks for the reply Carl and Dan. Although after reading each reply I really felt like we really were not on the same page when it came to some of the questions and comments I made.
So how about I simplify things and perhaps try and explain myself a bit better.
Ok , so forgetting everything.

Let's say I had a group of deuterium protons fairly close together.
( how this was achieved is not important).
What I want to do is crush or fuse-crush the protons together with the force of vacuum.
Eg. An example would be my hand ( the vacuum) crushing the plum ( protons).

P.s. Thanks Dan so much for the info on deuterium reactions. But without being big headed wouldn't you choose a harder reaction with the ability to use the photoelectric affect over neutrons heating a oil of some description.

James.

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Re: starts with vacuum theroy, am i looking at it wrong, or just a unique veiw.

Post by Doug Coulter » Tue Jan 08, 2013 4:48 pm

You were right about not being a big reader.
Carl and Dan just wrote you the most succinct and correct summaries of how this works I've ever read, and they are dead on. There's a lot more complexity behind their descriptions, but those should get you started on understanding.

Vacuum doesn't crush anything - it's a lack of pressure. Deuterium ions are very repulsive (like charges) and need to be accelerated at one another (which is why we ionize them, we don't have a way to put speed on neutral atoms anywhere near as easily as an E-field).

We use D because it is the easiest to fuse there is (high cross section) and because we get this signature signal - the neutrons - that doesn't otherwise appear in nature, thus it's the ideal way to measure how well you are doing. Could you learn to sing or play guitar if you were deaf?

We are lucky the sun isn't mostly D, as it would then simply explode. Richard has mentioned here the power output of the sun per CC, and all our fusors exceed that by many, many, orders of magnitude.

And of course, if you think we're all wrong, the obvious and highly encouraged solution to that is to get yourself into the lab and prove it - we're all ears when it comes to actual data, not so much so for theories from people who don't seem to get the basics that are well known and replicated throughout all science.
Why guess when you can know? Measure!

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Re: starts with vacuum theroy, am i looking at it wrong, or just a unique veiw.

Post by Richard Hull » Tue Jan 08, 2013 6:48 pm

Again three folks have tried to explain fusion to someone who seems as if they are trying to understand. If you find their expositions difficult or abstract, as Doug notes, there is much more detail far beyond what they posted.

The plum example is a very poor choice. The proton in and of itself doesn't respond in any way to a vacuum or intense pressure, as noted. The plumb is not crushed by a vacuum at all. The plum is mostly water probably 99.9% by weight. Water can only exist in a deep vacuum as a molecular gas. Thus, when a plum is placed in a vacuum chamber and it is pumped down, all the water evaporates into a gas phase leaving behind a tiny shriveled up shell. Your vacuum pump oil is treated to a lot of free water vapor, demanding a change of oil.

You haven't crushed a plum with the vacuum. You have removed most of its mass and sent it into the increasing vacuum as water vapor. The bulk of the plum's mass is now moved into the oil and on all the surfaces of the vacuum system.

The proton itself is not squeezed or made smaller under 1 million atmospheres of pressure nor is it expanded in the intergalactic vacuum of space. It just doesn't see such mechanical things.

Richard Hull
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Fusion is the energy of the future....and it always will be
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Re: starts with vacuum theroy, am i looking at it wrong, or just a unique veiw.

Post by electron » Tue Jan 08, 2013 8:21 pm

Ok so using vacuum to crush the protons together isnt the smartest idea ever.
Just don't forget the fusor is 98 % insufficient so I don't see why trying another way of fusing is such a bad thing. I understand I'm new here but it doesn't mean I don't understand the basic approach.

Perhaps I could use a magnetic field instead of vacuum.!

Either way I still struggle to see how you are going to fuse at break even especially when all your doing is accelerating protons together. You have the barrier and tunneling plus the inner grid all preventing this.
Not to mention all the failed attempts.

It's has been nice taking to you guys though.
Ill do more reading. Ok.

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Re: starts with vacuum theroy, am i looking at it wrong, or just a unique veiw.

Post by Chris Bradley » Tue Jan 08, 2013 8:33 pm

james brown wrote:
> I understand I'm new here but it doesn't mean I don't understand the basic approach.
> Perhaps I could use a magnetic field instead of vacuum.!
I don't want to sound harsh, but I am afraid that, in this case, it does mean you do not understand the basic approach.

Work needs to be done on the deuterons to raise their energy to fusible levels. An enclosed vessel does no net work on the gas inside it. Nor can a static magnetic field perform work on charged particles.

Work must be done on the particles in a fusor, and that only comes from an electric field.

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Re: starts with vacuum theroy, am i looking at it wrong, or just a unique veiw.

Post by Richard Hull » Tue Jan 08, 2013 9:11 pm

James any approach you can think of has pretty much been wrung out. The novel approaches you have already suggested are just flat out impossible based on the simple physics of it all.

It sounds like you think we are here to break even or get nuclear power or just improve the fusor. You used the term 98 percent insufficient. I assume you mean 98% inefficient. Well, its worse than that! We are about 99.99999% inefficient. We waste about 10 million times the electric power into the machine as to the amount of fusion energy that comes out. If we got 2 percent efficient, as you noted, the fusor would have probably killed a bunch of us here from lethal neutron radiation. Oh, but that the fusor wasted only 98% of its input energy! Wow!.... That would be roughly 10 million times better than we are doing now.

Every living breathing entity here knows the fusor will never approach 2% efficiency wasting 98% of its input power. That is a wonderful dream, but it will never happen.

Even the most hopeful here know the fusor will never produce any usable energy.....Ever! We are just not on that quest.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
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Re: starts with vacuum theroy, am i looking at it wrong, or just a unique veiw.

Post by electron » Tue Jan 08, 2013 9:56 pm

That's really sad.

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