Hey Indrek. Once Again amazing work, seriously. I have been working on the electron injection amongst other things and seeing the dynamics of the electric charge surrounding the coils is invaluable.
So, previously you have done some basic sims of the positive electric field around the machine. But these didnt take into account actually having anything inside the machine
So now you put a 0.1m conducting sphere in the centre of the machine to basically emulate a wiffle ball and then calculated how the electric field would change with various charges. Is this correct ?
What led you to assume a 0.1m radius. Of course the WB is going to vary in size with respect to B field intensity and the number of electrons injected at x energy. Does anyone know what the minimum and maximum sizes a wiffle ball could be ? Will you do another run with varying diameter conducting spheres.
By the way great work also @ http://www.mare.ee/indrek/ephi/bfs/ its what got me thinking about this wiffle ball size issue. Its going to be very important
wiffle ball size = electron cloud size/density = ion cloud size/density(combined with POPS)= Fusion output
Fusion output = Direct power conversion efficiency = Power for B fields, E guns I guns = wiffle ball size.
Its not meant to be an equation, but everyting goes round and round. We gotta keep thinking from a net power perspective.
Virtual Polywell
That's correct. But it's not a conducting sphere (where charge is on the surface) but a sphere of uniform charge (charge density within the ball is nonzero and constant). Why a 0.1m radius? A random guess. Also a uniform charge distribution is easy to handle and visualize as the field does not go to infinity in the middle would it have been a point charge. As for calculating the coil charge and fields outside the radius is irrelevant as outside the sphere it effects as a simple point charge.So now you put a 0.1m conducting sphere in the centre of the machine to basically emulate a wiffle ball and then calculated how the electric field would change with various charges. Is this correct ?
- Indrek
I've only got a few plots of the "force volume", but it looks like the force field near the cusps and centers of the magnets points towards the center of the fusor for electrons and a "typical" grid at 20kV with 150 amp turns. I'll have to look closer to the coils to see if the v x B dominates - that's kind of the whole point to avoid electron flux onto the grid.
The general equations seem like they should apply for any species, electron, proton or boron. Adding sources and sinks for ionization and neutralization should also be "straight forward", at least for a computer model. I'll try to write it up and post it soon - I'm not sure how long it will take.
The general equations seem like they should apply for any species, electron, proton or boron. Adding sources and sinks for ionization and neutralization should also be "straight forward", at least for a computer model. I'll try to write it up and post it soon - I'm not sure how long it will take.
I have a first write up which explains what I've tried to do on modeling the polywell. It can be found here:
http://www.eskimo.com/~eresrch/Fusion/fusion.pdf.
It's obviously pretty crude, but it's a start. Comments on how to improve things are welcome!
http://www.eskimo.com/~eresrch/Fusion/fusion.pdf.
It's obviously pretty crude, but it's a start. Comments on how to improve things are welcome!
No gun electron injection.
This seems like a good place to ask the question.
Is there a way to keep an excess of electrons in the system without electron guns?
The problem with guns in a power reactor is shielding them from alpha bombardment. If we could do away with guns it would be a big help in design.
Is there a way to keep an excess of electrons in the system without electron guns?
The problem with guns in a power reactor is shielding them from alpha bombardment. If we could do away with guns it would be a big help in design.
Dr mike i just read your paper and i think i will have to quote
"Before I came here I was confused about this subject. Having listened to your lecture I am still confused. But on a higher level." - Enrico Fermi
Nanos, FELs require massive magnets called wigglers. These alone would consume about as much power as the polywell coils. Im not even sure if one has been made yet.
Msimon (or anyone else) on the subject of the electron guns could you take a REALLY CLOSE look HERE (large)
What are the 4 pipes hanging down from the top of the machine ? Im guessing gas injection ? I dont see any electron guns in that picture. From the data it seems like they only had one big e-gun, and it isnt in the picture. It must of been outside the grid.
How would some sharp angular panels F-117 nighthawk style go protecting the E-guns ?
"Before I came here I was confused about this subject. Having listened to your lecture I am still confused. But on a higher level." - Enrico Fermi
Nanos, FELs require massive magnets called wigglers. These alone would consume about as much power as the polywell coils. Im not even sure if one has been made yet.
Msimon (or anyone else) on the subject of the electron guns could you take a REALLY CLOSE look HERE (large)
What are the 4 pipes hanging down from the top of the machine ? Im guessing gas injection ? I dont see any electron guns in that picture. From the data it seems like they only had one big e-gun, and it isnt in the picture. It must of been outside the grid.
How would some sharp angular panels F-117 nighthawk style go protecting the E-guns ?
Purity is Power
An electron gun outside of the faraday cage wouldn't make much sense.What are the 4 pipes hanging down from the top of the machine ? Im guessing gas injection ? I dont see any electron guns in that picture. From the data it seems like they only had one big e-gun, and it isnt in the picture. It must of been outside the grid.
As I understand it does four pipes are the electron guns, I only read about trouble with one fuel injection valve not four
The fuel needs to get ionised inside of the coils or the ions will have enough energy to leave the well, thus fuel injection probably went over the fifth pipe ending closer to the MA-grid.
What would be the main problem with alphas hiting the e-guns?The problem with guns in a power reactor is shielding them from alpha bombardment. If we could do away with guns it would be a big help in design.
Heat, loss current, material degration or something different?
If it's only the loss current it shouldn't be too bad, the surface of the e-guns should be relative small and thus the corresponding ion current much smaller than the one to the extraction grids.
In fact I wonder whether the alphas wouldn't increase the electron current by 'hitting' electrons out of the metal.
By the way, wouldn't 100 MW in ~3MeV alphas produce massive outgasing?
Anyway I don't see how it could be done, of course an electron source could be placed in the shadow of the MA-grid, but I think there was something in the valencia paper about well depth being strongly affected by the angle at which the electrons enter the wiffleball, so that probably is a bad approach.
Shielding with h-fields seems pretty impossible to me, a field designed to keep 3 MeV alphas away probably won't let electrons go very far.
Stephan,
The fields would be very localized. However you are probably correct.
The more I think about it the more it seems that RF ionization might be the answer. There is still the question of how to maintain an excess of electrons.
The main problem with alphas hitting the e guns in a power reactor is heat dissipation.
The fields would be very localized. However you are probably correct.
The more I think about it the more it seems that RF ionization might be the answer. There is still the question of how to maintain an excess of electrons.
The main problem with alphas hitting the e guns in a power reactor is heat dissipation.
Keegan, If I could confuse Fermi I'd be pretty happy 
I would guess the 4 pipes lead out to those balls which are at the cusps. I would guess they are Langmuir probes for measuring electron and ion densities.
MSimon, I think there is a way. If the electron energy is high enough to ionize the H and B gas, but not too high to escape the magnetic trapping, then it can continously circulate. Initial ionization can come from microwaves, which is something already proposed in another thread here. A large pulse to start it up and then the energy from the fusion could easily keep it going.
One of the things I want to do at this point is follow the electron fluid in the super crude model. If it circulates without running into the walls (I may have to move the walls ) then running without electron guns makes a lot of sense.
Adding the ion fluid should be "straight forward". Adding sources and sinks for ionization and recapture should also be possible. So I think a basic polywell can be found that meets fundamental requirements of stability. Then it is a matter of finding the correct scale to meet the fusion requirements.
It's still crude, but it can point the way towards a functioning device and away from things that obviously won't work. The latter is what I consider more important!
BTW, thanks for reading it!
I would guess the 4 pipes lead out to those balls which are at the cusps. I would guess they are Langmuir probes for measuring electron and ion densities.
MSimon, I think there is a way. If the electron energy is high enough to ionize the H and B gas, but not too high to escape the magnetic trapping, then it can continously circulate. Initial ionization can come from microwaves, which is something already proposed in another thread here. A large pulse to start it up and then the energy from the fusion could easily keep it going.
One of the things I want to do at this point is follow the electron fluid in the super crude model. If it circulates without running into the walls (I may have to move the walls
) then running without electron guns makes a lot of sense. Adding the ion fluid should be "straight forward". Adding sources and sinks for ionization and recapture should also be possible. So I think a basic polywell can be found that meets fundamental requirements of stability. Then it is a matter of finding the correct scale to meet the fusion requirements.
It's still crude, but it can point the way towards a functioning device and away from things that obviously won't work. The latter is what I consider more important!
BTW, thanks for reading it!