Posted: Thu Jul 17, 2008 5:47 pm
In my previous post I mentioned convergence was hard not impossible.
Firstly there may be a possiblity that much like a bubble adopts a spherical shape due to the fact that it is the most affective way to resist the external pressure of the water, the wiffleball in the beta=1 condition could achieve a shape that is more far spherical then the external magnetic field in the absence of a plasma. By eye this seems to be the case. Whether this spherical looking blob is spherical enough to achieve fusion is another issue that, I believe, has not yet been meassured precisely.
Ramping up the density reduces the number of passes required for fusion the very presence of convergence would reduce that number still further.
I started a thread here:
http://talk-polywell.org/bb/viewtopic.php?t=467
mentioning the possibility of getting a mono-energetic distribution of ions by injecting neutrals from a convergent beam into the region of zero field at fusion energies and ionizing them at the bottom of the potential step.
If you do want an electric field you could shrink the polywell in size down to a debye length. That would mess up your ratio of cusp to total surface area though. I toyed with the idea of a "Polywell matrix", plugging the cusps of one mini-Polywell into the others. If you create a lattice of truncated cubes the interstices in between are octahedral.
I don't agree that Chacon proved that electric fields could be maintained at distances in excess of the Debye length, infact I read the chacon paper that was referred to, the electron densities were 10^18/m^3, the temperatures were 100kV and the diameter of the device was 1cm. Infact in that paper he stated that a Penning trap was a Debye length Machine.
I know that in a tokamak radial electric fields can be sustained at distances far greater that the Debye length, but this is because the two fluid equations mean that not having them would violate the law of conservation of angular momentum. This is not the case in a Polywell.
I would be interested to read of any experimental cases where centrally convergent electric field have been measured over distances far in excess of the Debye length in any plasma system.
Annealing
If the ions slow down at the same radius at the same time, the density would indeed be huge, if they slow down at the same radius at different times the density will not exceed that in the core (unless they are very cold indeed)
There may be thermal expansion of this edge at high density into the regions of lower density, but if the temperature the edge is 1eV say, this free expansion could be quite slow.
I still say the condition required for convergence are very delicate and probably can't be achieved in some cheap and nasty way.
Firstly there may be a possiblity that much like a bubble adopts a spherical shape due to the fact that it is the most affective way to resist the external pressure of the water, the wiffleball in the beta=1 condition could achieve a shape that is more far spherical then the external magnetic field in the absence of a plasma. By eye this seems to be the case. Whether this spherical looking blob is spherical enough to achieve fusion is another issue that, I believe, has not yet been meassured precisely.
Ramping up the density reduces the number of passes required for fusion the very presence of convergence would reduce that number still further.
I started a thread here:
http://talk-polywell.org/bb/viewtopic.php?t=467
mentioning the possibility of getting a mono-energetic distribution of ions by injecting neutrals from a convergent beam into the region of zero field at fusion energies and ionizing them at the bottom of the potential step.
If you do want an electric field you could shrink the polywell in size down to a debye length. That would mess up your ratio of cusp to total surface area though. I toyed with the idea of a "Polywell matrix", plugging the cusps of one mini-Polywell into the others. If you create a lattice of truncated cubes the interstices in between are octahedral.
I don't agree that Chacon proved that electric fields could be maintained at distances in excess of the Debye length, infact I read the chacon paper that was referred to, the electron densities were 10^18/m^3, the temperatures were 100kV and the diameter of the device was 1cm. Infact in that paper he stated that a Penning trap was a Debye length Machine.
I know that in a tokamak radial electric fields can be sustained at distances far greater that the Debye length, but this is because the two fluid equations mean that not having them would violate the law of conservation of angular momentum. This is not the case in a Polywell.
I would be interested to read of any experimental cases where centrally convergent electric field have been measured over distances far in excess of the Debye length in any plasma system.
Annealing
If the ions slow down at the same radius at the same time, the density would indeed be huge, if they slow down at the same radius at different times the density will not exceed that in the core (unless they are very cold indeed)
There may be thermal expansion of this edge at high density into the regions of lower density, but if the temperature the edge is 1eV say, this free expansion could be quite slow.
I still say the condition required for convergence are very delicate and probably can't be achieved in some cheap and nasty way.