Centrifugal Confinement

[Ivy Matt]

I found this one about five months back. Its inventor calls it the “Pressurized Rotating Fusion Reactor” (PRFR) and refers to the concept as “centrifugal confinement”. He was apparently granted a patent for it in August:

Pressurized Rotating Fusion Reactor

I think it’s an odd concept, yet it appeals to me much more than, say, General Fusion’s approach. The University of Maryland’s “Maryland Centrifugal Experiment” (MCX) uses a slightly similar approach:

Maryland Centrifugal Experiment

[KeithPickering]

Lardenoit’s idea seems like more wishful thinking. No magnetic fields? In that case, what keeps the plasma from touching the wall of the sphere? Nothing, apparently. And when that happens, the ions pick up electrons, become electrically neutral, and whammo, no more plasma. Sorry, no fusion here.

The Maryland experiment seems reasonable: use centrifugal forces to augment the magnetic field, rather than replace it outright. Might lead to interesting results, but again it’s an experiment, not a reactor.

[Ivy Matt]

Well, according to the hypothesis, the plasma in the center is never supposed to touch the wall of the container because there’s a gradient of slightly cooler but more dense plasmas and gases filling the vessel from the center to the walls, and the centrifugal force keeps the coolest, densest gases against the container walls and the hottest, least dense plasmas in the center. The plasma in the center is confined by the cooler and slightly denser plasma that immediately surrounds it, not by the container wall.

That’s the hypothesis, anyway. From my perspective as a non-scientist, I can see that it may not work that way, but not that it necessarily won’t work that way. Possible problems that I see: 1) Centrifuges may not separate out plasmas and gases the way they do liquids and solids, so central D-T plasma is never formed. 2) Separation may work on the elements, but thermalization bleeds energy away from the center of the vessel too quickly for fusion to happen.

[jamesr]

I agree with Keith – there s no way this has a chance of confining a plasma.

First you have the ‘hairy ball problem’ – there is no way to make a 3D spherical rotating field that does not leak at the poles (even if the the axis of rotation is itself rotating along another axis). Also if you have a large mass rotating then conservation of angular momentum ie. gyroscope effect, means you have to exert a large force to tilt the inner rotating sphere about another axis.

Secondly, unless you are at the densities of inertial fusion, then the average distance between ions & electrons colliding at fusion temperatures is huge. In a normal tokamak an ion may go around thousands of times before scattering (or very occasionally fusing) with another ion. This equates to km of distance traveled. So unless you have a magnetic field bending its path back on itself then a ‘hot’ ion will just carry on in a straight line until it hits something else, ie the dense wall.

[Ivy Matt]

Thanks for the explanation! I think I’ve got it.

[tim Lardenoit]

First of all , most energy losses is due to bremsstrahlung radiation, so whatever your confinement method will be, you need to put energy in the plasma in effort to keep the plasma. in this concept it is done with a gyrotron, a big microwave oven that give ions more energy. Another thing with this concept is the pressure, in a tokamak the pressure is only 2 to 5 bar. with this concept the pressure is 100 times higher resulting in a fusion rate 10 000 times higher. The neutron flux is also 10 000 times higher, so the plasma absorb neutron energy in effort to be self-sustaining. Then the hairball effect will be studied in my test setup which will be finished the end of this year. Then i will post a video on you-tube. A next step is to put a Jacobs ladder in a 3-D centrifugal field and give physical evidence that the confinement method is the way to go.

[Ivy Matt]

In my opinion, it’s always a good thing for ideas to move past the conceptual stage to the experimental stage. So, good luck! I must confess, though, I’m not sure I understand what purpose the Jacob’s ladder serves.

[tim Lardenoit]

the jacobs ladder is to ionize the air and create a spherical plasma. In normal conditions the Archimedes forces puling the plasma out the jacobs ladder and create a new arc. With the centrifugal forces the plasma is kept in the center, if my theory is correct…

[jamesr]

I don’t mean to be harsh, but can an admin move this thread to the Noise & ZPE category.

[Aeronaut]

Aw, Jamesr, if we move it to the noise category, we’d have to move anything and everything DT-related there, too. :ohh:

[jamesr]

No, it is more the fact that the centrifuge concept is so fundamentally flawed that it should not be along side concepts like RFP, polywell etc. which can at least confine a plasma and get some fusion, even if they have little real chance of producing nett energy gain.

[tim Lardenoit]

james, have you ever seen a lighting? its a non confined plasma to, so don’t just say it cannot work. You simply don’t know…

[jamesr]

tim Lardenoit wrote: james, have you ever seen a lighting? its a non confined plasma to, so don’t just say it cannot work. You simply don’t know…

And a glowing neon lamp contains a plasma, but this is a world away from fusion capable plasma conditions.

Ignoring for a minute the impossibility of having a spherically symmetric pressure on the walls – your diagram shows the outer shell containing water at ~250bar. To contain this the wall would have to be many inches of steel, or similar. You then propose heating the core using microwaves. How are the microwaves supposed to travel through the containing wall and water?? In order to couple and heat a plasma an RF antenna must be within a few ion skin depths of the plasma, otherwise it is just reflected back.

[tim Lardenoit]

Well, that are solvable engineering problems. If you have two halve rotating sphere’s you can bring a RF antenna and the ion feeding system between it, like the picture left below on the site. and if you put the whole rotating thing in a second pressure vessel, the rotating vessel can be build thin.

[Aeronaut]

Sounds like something the government might be interested in. Radioactive fuel, radioactive waste, big budget, no timeframe, everything seems to check, all the way down to requiring the steam turbines.

[Author]

Posts