## Energy conversion...

Point out news stories, on the net or in mainstream media, related to polywell fusion.

Moderators: tonybarry, MSimon

chrismb
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MSimon wrote:
chrismb wrote:
KitemanSA wrote: IIRC, the discussions back then spent a significant effort on handling the distribution of energies. Don't condemn until you read.
I read, commented, re-read, re-commented, &c. and now feel well placed to condemn. Show me the extra-ordinary proof this extra-ordinary thing can work, and whoever does so will get a "fancy that, it works!!" out of me.
It is not extraordinary chris. As far as I can tell it is just electrostatics. If you can accelerate particles with electrostatics why can't you decelerate them?
You can. But which *one* particle energy. Yeah, I can read what it is aiming to do with gradual blinds, but then that leaves a shed-load of neutral particles kicking around that will diffuse back into the device and contaminate it. If a neutral helium gets re-ionised within the working volume, it will never escape.

MSimon
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chrismb wrote:
MSimon wrote:
chrismb wrote: I read, commented, re-read, re-commented, &c. and now feel well placed to condemn. Show me the extra-ordinary proof this extra-ordinary thing can work, and whoever does so will get a "fancy that, it works!!" out of me.
It is not extraordinary chris. As far as I can tell it is just electrostatics. If you can accelerate particles with electrostatics why can't you decelerate them?
You can. But which *one* particle energy. Yeah, I can read what it is aiming to do with gradual blinds, but then that leaves a shed-load of neutral particles kicking around that will diffuse back into the device and contaminate it. If a neutral helium gets re-ionised within the working volume, it will never escape.
I agree. There are problems. And there will be quite a bit of heat to dump. And culling He out of the reactor will be a problem.

Tom Ligon has suggested that continuous operation might not be in the cards. I didn't like hearing that. He may be right.
Engineering is the art of making what you want from what you can get at a profit.

DeltaV
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Joined: Mon Oct 12, 2009 5:05 am
Maybe by modifying the B and/or E field of one of the magrid coils we can get a "jet mode", as can be obtained with wire-grid fusors. This might reduce the magrid heat load, improve He purging, and allow for continuous operation.

http://www.n-plasma.com/plasma_jet.html

tombo
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Location: Washington USA
Just thinking out loud here:

Assume a wide alpha beam coming out of a cusp with a radius of about the gyro radius. (That is how MSimon estimated the beam diameter above.)
The alphas should all be orbiting the same direction.
The higher energy alphas will have a larger gyro radius than the lower energy ones.
So, the alphas should already be separated spatially by energy. (albeit not perfectly)

1. Collector is sets of thin plates radial to the beam axis running longitudinally.
Each set starts with a short (in the radial dimension) plate to collect the larger radius higher energy ones at at higher voltage.
Moving in the angular direction it is followed by a longer plate (i.e. reaching closer to the axis of the beam) at a slightly lower voltage.
Those are followed by consecutively longer and lower voltage plates like stair steps approaching the axis.

The number of plates in each set and the number of sets placed around each beam would depend on the efficiency desired and efficiency possible due to beam spread in space and energy.
The helix angle of the alphas must also be considered. Anyone know what it is? Or what range of angles might show up?

2. It might be better to arrange the different sized plates axially along the beam starting with the small ones and proceeding to bigger ones (closer to the axis) as we move (axially along the beam) further from the core.

3. The beam would expand further from the PW as the field gets weaker.
So, maybe just a tube of segments at different voltages. Just running the machine would automatically charge the segments to the correct voltages.

4. Ideally the beam should be collimated as tightly as possible before separating it by voltage.
Say, particle beam guys, is this possible?

5. I know this is really stretching it but...
Next: Spin the collector and reshape it to make it into the first stage of a turbo pump to solve the He scavenging problem.
Yes, there will be a few difficulties , like I'm not sure how to make the high voltage high rpm rotating contacts, and the structural issues due to the high rpm combined with the geometry constraints from trying to be both the collector and the pump vanes will be interesting.

(I know I've said it before but I hate using English to describe geometry. Maybe I'll try to draw it.
Morphing the plates into turbo pump vanes might be a little tricky . I'm imagining something a little like the turbine wheel in an automobile's turbocharger but inside out and split into different voltage strips somehow. Maybe...)

I would like to hear someone who is familiar with quadrupole mass spectrometers speculate on a separator based on that technology.
-Tom Boydston-
"If we knew what we were doing, it wouldn’t be called research, would it?" ~Albert Einstein

MSimon
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I would like to hear someone who is familiar with quadrupole mass spectrometers speculate on a separator based on that technology.
I was considering that but you need to get the He neutralized and then reionized at some low thermal energy - a few eV at most.

I'm going to have to get my MS books out I guess.
Engineering is the art of making what you want from what you can get at a profit.

DeltaV
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tombo wrote:The helix angle of the alphas must also be considered.
This sounds like a job for Fluxomatic (formerly known as The Amazing Dial-A-Flux).
viewtopic.php?t=1570
I forego all patent protection in the interest of humanity and my bank account.

tombo
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Location: Washington USA
This sounds like a job for Fluxomatic
I don't understand it. But it seems to be able to adjust to focus one ion type on a point.
But the other ions are not focused anywhere.
We have all the same ion type but want different energies to be focused at different locations.
Do you understand the "Fluxomatic" well enough to be able to say it does that?
-Tom Boydston-
"If we knew what we were doing, it wouldn’t be called research, would it?" ~Albert Einstein

DeltaV
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If I could answer 'yes' to that I'd be a fusion physicist.

This is a better demo than the one in the above link:
http://demonstrations.wolfram.com/BarsOfAHyperboloid/

I don't know if we can ascribe any 'focusing' effect to Fluxomatic (though there may be some combination of parameters that does this).

I was thinking more of an alpha particle collector and/or 'valve' using thin 'venetian blind' slats instead of the 'bars' in the demo. The outer ring/coil having a larger diameter than the inner ring/coil (so it's in the magrid shadow).

There are lots and lots of parameters that could be varied with something like this. Mechanical ones (outer ring diameter, distance between outer-inner rings, number of 'slats', overall hyperboloid twist angle, slat rotation angle, slat twist angle, ...) and electrical ones (potential on each ring/coil case, coil currents, paths of currents through the array of slats, modulation of the slat currents, ...).

This is a job for patient/wealthy experimentalists and Los Alamos-class supercomputers, once the mechanical details have been worked out.

DeltaV
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tombo wrote:But it seems to be able to adjust to focus one ion type on a point.
A near-cone shape is probably not attainable for a "helicon" short enough to be enclosed by the magnetic envelope of the two end coils.
Assuming here that the "helicon" or slats must be magnetically shielded to avoid killing the recirculating/oscillating electrons. For an alpha collector you'd want the slats at least partially uninsulated. For some other use (resonance tuner?) you'd probably want the bars to be fully insulated to avoid plasma shorts.

MSimon
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DeltaV wrote:
tombo wrote:But it seems to be able to adjust to focus one ion type on a point.
A near-cone shape is probably not attainable for a "helicon" short enough to be enclosed by the magnetic envelope of the two end coils.
Assuming here that the "helicon" or slats must be magnetically shielded to avoid killing the recirculating/oscillating electrons. For an alpha collector you'd want the slats at least partially uninsulated. For some other use (resonance tuner?) you'd probably want the bars to be fully insulated to avoid plasma shorts.
I think that can be handled by more grids. Add a 0 V grid between the collector apparatus and the MaGrid.
Engineering is the art of making what you want from what you can get at a profit.

MSimon
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Steer the crazy odd voltage streams of Helium debris with some toroidal magnets and put that hot soup of particles to the heat exchanger for an efficient Brayton cycle. If it doesn't stick to the blinds and provide work, focus it and provide some work as heat at least. Reclaim some of the waste heat.
A thermal cycle is bad news for costs and deployment logistics. Steam/thermal plants are long lead items.
Engineering is the art of making what you want from what you can get at a profit.

Heath_h49008
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Location: Michigan
I think we can come up with some better ways use He at high energy than boiling water.

What % of output are we dealing with? I apologize for my inability to find a good formula, or come up with one of my own.

How much energy is left in the He product, and how much will be produced as each other form of radiated particle?

It should be a fairly basic bit, I just can't find it. I don't believe we are really dealing with much He at all, and what we do get, should be easy to "Filter" before we pump any B11 or Hydrogen back into the core. We can't exactly waste all that fuel. (Or can we?)

How much are we really going to be losing from a WB, running in steady state, with a stable well in the middle, and the cusps squeezed tight?

Some, yes... But how much?

MSimon
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Heath_h49008 wrote:I think we can come up with some better ways use He at high energy than boiling water.

What % of output are we dealing with? I apologize for my inability to find a good formula, or come up with one of my own.

How much energy is left in the He product, and how much will be produced as each other form of radiated particle?

It should be a fairly basic bit, I just can't find it. I don't believe we are really dealing with much He at all, and what we do get, should be easy to "Filter" before we pump any B11 or Hydrogen back into the core. We can't exactly waste all that fuel. (Or can we?)

How much are we really going to be losing from a WB, running in steady state, with a stable well in the middle, and the cusps squeezed tight?

Some, yes... But how much?
Neutron energy is .1% of the total. Maybe less. Not significant except for materials used. i.e. neutron activation.
Engineering is the art of making what you want from what you can get at a profit.

DeltaV
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It's way past my bedtime, and I'm caffeine-deficient to boot (only had 4 large mugs today), so I should probably sleep on this, but I'll forget it by morning...

Somehow rig the inner coil case so that the portion connected to the hyperboloid links/bars can rotate with the links (bulk rotation, distinct from twist). Connect a rotating outer coil to the rotating inner coil portion with non-conducting but structurally sound links that can briefly retain a surface charge when impacted by alphas. Optimize the hyperboloid twist angle, outer coil diameter, link spacing, etc. for alpha charge accumulation. The combined inner-outer coil B field (enveloping the coils and links) is assumed here to shield against electron collisions but not alpha collisions. The spinning assembly is the rotor of an electrostatic motor. The stator would be arranged around the outside of the rotating hyperboloid, presumedly also within the B field shielding from the coils. Maybe Jefimenko's hope of 1000 HP/m^3 could be exceeded:
viewtopic.php?p=31238&highlight=#31238
(Don't expect to see a lot of equations if you locate his book, it's more of a historical document.)

If you assume the direct conversion grids lie beyond the outer coil, there's also the possibility of varying the power extraction ratio (electrostatic motor for mechanical power out vs. direct conversion for UHVDC out) via the hyperboloid twist angle, which might suit a dual-mode flying machine (aircraft/QED-ARC SSTO). The hyperboloid could be twisted to dip into the alpha stream for times when UHVDC would not be suitable. Whew, I feel like Tesla.

 I'm assuming here that power needed for aircraft mode is significantly less than that needed for SSTO mode. So at low altitudes, where long term use of QED-ARC causes ozone issues and tickets from the Green Police, run the Polywell at reduced output and capture just a fraction of the alphas to power electrostatic motors inside the vacuum chamber. These then drive either lift fans/turbines directly OR efficient low-voltage generators connected to efficient low-voltage motors connected to lift fans/turbines. Having futzed about indefinitely in the lower atmosphere, one then maxes out altitude/speed in motor mode (this is a transient phase, so higher than normal heat loads are tolerable), untwists the hyperboloids (vehicle coasting, but all alphas can now go for direct conversion), cocoons the turbines, throttles up the Polywell and fires QED-ARC using all the alphas that can be direct-converted for the REB. YeeeeeeHaaaaaa!
Last edited by DeltaV on Wed Feb 10, 2010 7:28 pm, edited 2 times in total.