Along with RFC recently in the news, there is some additional information about the Dense Plasma Focus at the below link.
The physics seems to be reasonable (hearsay), but the engeenering of handling rather large bangs every time the device fires at near breakeven levels seems intimidating (see comments at bottom).
http://nextbigfuture.com/2009/08/previo ... earch.html
Since Rupp has worked with this approach it might be interesting reading, if not already explored.
viewtopic.php?f=15&t=7206&hilit=dense+p ... cus#p51309
Dan Tibbets
Dense Plasma Focus info
Re: Dense Plasma Focus info
Some news from Eric Lerner DPF
http://www.lawrencevilleplasmaphysics.c ... &Itemid=90
One interesting image is shown toward the end of the video where someone holds a bubble detector tube in his hand.
My question is: is there enough security in this lab for such fusion level?
I did not read everything on their site yet, but this looks like high bubble count.
http://www.lawrencevilleplasmaphysics.c ... &Itemid=90
One interesting image is shown toward the end of the video where someone holds a bubble detector tube in his hand.
My question is: is there enough security in this lab for such fusion level?
I did not read everything on their site yet, but this looks like high bubble count.
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Dan Tibbets
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Re: Dense Plasma Focus info
I don't know the sensitivity of the bubble detector, but guessing that was perhaps 1/2 meter away, and the small area of the total equivalent area of a sphere at that distance, and the duration of perhaps 10 nonoseconds for the test, then yes. it is a lot of neutrons. Probably equivalent to billions, if not trillions of fusions per second. But, remember these are extreamly short tests. Total exposure is probably ~ same as the typical good amautuer fusor running for some minutes.
And yes, there is shielding. The reactor is in a concrete and ? chamber. Did you notice them traversing two corners to enter/ exit the test chamber. In a DPF, there may be nearly as much energy released in X- rays (bremsstrulung) as fusion particles., So, I assume there is some lead or other heavy metel in the walls.
[EDIT] Errr. ..at least there will be a lot of Bremsstrung radiation if they test P-B11. With deuterium at ~ 30,000 volts, the x-rays are probably not to bad. Few probably get through the vacuum vessel.
Dan Tibbets
And yes, there is shielding. The reactor is in a concrete and ? chamber. Did you notice them traversing two corners to enter/ exit the test chamber. In a DPF, there may be nearly as much energy released in X- rays (bremsstrulung) as fusion particles., So, I assume there is some lead or other heavy metel in the walls.
[EDIT] Errr. ..at least there will be a lot of Bremsstrung radiation if they test P-B11. With deuterium at ~ 30,000 volts, the x-rays are probably not to bad. Few probably get through the vacuum vessel.
Dan Tibbets
Re: Dense Plasma Focus info
Thank you for your comments.
Using this rough approximation, I get ~0.3 microjoules of fusion energy produced in one shot. Their goal if for break-even in 2011. Possible or not?
Using this rough approximation, I get ~0.3 microjoules of fusion energy produced in one shot. Their goal if for break-even in 2011. Possible or not?
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Dan Tibbets
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Re: Dense Plasma Focus info
Possible?
Yes, if you accept their assumptions and predictions. The fusion power apparently scales logarithmically with increased input energy(up to a limit). Other labs have studied DPF and I don't think they have been as optimistic as this lab. There are a few variations that they are pursuing that may boost their output. Introducing an angular momentum to the plasma may help, and they have achieved pre plasma gas densities higher than expected (could lead to more dense plasmoids?).
In the unlikely event that they actually reach their single shot goals, it would be interesting and possibly a good source of neutrons for various purposes.
But, for useful power production they would still have to repeat the pulses perhaps thousands of times per second. And the electrodes erode fast. A machine might work but have a lifetime of only seconds before the electrodes have to be replaced.
If they do reach their Q goals they will still have to have high efficiency waste energy (heat and X-rays) recovery to be pratical. Also, because of the way the machines may scale (the most optimistic estimates) they may be limited to a few megawatts of net power outputs. Apparently FRC approaches also suffer this limitation. If they work, this makes them less attractive for general power production, but they may be ideal for certain niche uses.
It is a Goldilocks type situation. DPF and FRC reactors are too amall, Tokamaks are to large, but Polywells, andperhaps General Fusion 's approach, and fusion -fission hybrids may be just right.
Speaking of fusion -fission (thorium) hybrids, a DPF or FRC system may be an ideal neutron source for these hybrid reactors , even if it doesn't reach breakeven on it's own.
But, compared to other labs (FRC, Polywell) they are presenting their progress and , frustrations with the public in a much more open manner, which is commendable.
Also, the pursuit of this approach to fusion is cheep. While it is beyond the budget of most amateur fusioneers, it is perhaps only one to two orders of magnitude greater. Other approaches are each progressively an order of magnitude more expensive than the prevous. DPF, Polywell (and possibly General Fusion's approach), FRC, Various spheromaks, and finally tokamaks (probably ~10,000to 30,000 times as expensive as DPF research.
Dan Tibbets
Yes, if you accept their assumptions and predictions. The fusion power apparently scales logarithmically with increased input energy(up to a limit). Other labs have studied DPF and I don't think they have been as optimistic as this lab. There are a few variations that they are pursuing that may boost their output. Introducing an angular momentum to the plasma may help, and they have achieved pre plasma gas densities higher than expected (could lead to more dense plasmoids?).
In the unlikely event that they actually reach their single shot goals, it would be interesting and possibly a good source of neutrons for various purposes.
But, for useful power production they would still have to repeat the pulses perhaps thousands of times per second. And the electrodes erode fast. A machine might work but have a lifetime of only seconds before the electrodes have to be replaced.
If they do reach their Q goals they will still have to have high efficiency waste energy (heat and X-rays) recovery to be pratical. Also, because of the way the machines may scale (the most optimistic estimates) they may be limited to a few megawatts of net power outputs. Apparently FRC approaches also suffer this limitation. If they work, this makes them less attractive for general power production, but they may be ideal for certain niche uses.
It is a Goldilocks type situation. DPF and FRC reactors are too amall, Tokamaks are to large, but Polywells, andperhaps General Fusion 's approach, and fusion -fission hybrids may be just right.
Speaking of fusion -fission (thorium) hybrids, a DPF or FRC system may be an ideal neutron source for these hybrid reactors , even if it doesn't reach breakeven on it's own.
But, compared to other labs (FRC, Polywell) they are presenting their progress and , frustrations with the public in a much more open manner, which is commendable.
Also, the pursuit of this approach to fusion is cheep. While it is beyond the budget of most amateur fusioneers, it is perhaps only one to two orders of magnitude greater. Other approaches are each progressively an order of magnitude more expensive than the prevous. DPF, Polywell (and possibly General Fusion's approach), FRC, Various spheromaks, and finally tokamaks (probably ~10,000to 30,000 times as expensive as DPF research.
Dan Tibbets