JMC
Pellet injection technology was largely developed at ORNL in the late 70s and early 80s. We've thought about this, but I suspect that the cost is a little pricey for our budget. There are a couple of other problems with this. One problem is that if assymetric high energy electrons impinge on a pellet (which will almost certainly be the case in a polywell) it is hard to control where they go. Also, the mass in these pellets would have to be a lot smaller than those used on tokamaks, so I doubt that an off-the-shelf design would be suitable. This is a problem and complication that we don't really want to deal with right now.
Another KOS Diary On IEC/Bussard
On WB4 and WB6: Yes I remember reading a report about this method of forming a wiffleball written by Dr. Bussard, I think this approach would allow a wiffle ball to be formed while having less plasma trapped in the fieldlines, has this method actually ever been implemented experimentally though? The former EMC^2 employee I spoke to said that they always tried to approach WB-mode from the MR-mode side while he was working there.
If you look at the picture of WB6 you can see it does have solid material linking the coils, it would be structurally impossible not to. This link is far smaller than it was in WB4 though, so corner losses are reduced, but I don't they were completely eliminated.
I have thought of a way which corner losses could be eliminated complete, by having an open box machine with the coils outside the vessel, the vacuum vessel would need to have a pretty crazy shape though.
On pellets: If WB-mode can be achieved with gas then I agree the best idea would be to try that first as it is less complicated. If not much luck is had with that method then maybe you could try dropping a pellet of water ice (which might be easier to produce) into a ready formed electron well where the electrons are all just rattling about, like I said, putting fusion aside for the moment just to see if a stable wiffleball can be formed.
I would imagine that collisions of the high energy anisotropic streams of electrons with the pellet material itself might tend to cause them to become more isotropic in anycase. But yes, the whole thing would probably be more of a back up plan if stable wiffleball formation could not be achieved with the gas.
If you look at the picture of WB6 you can see it does have solid material linking the coils, it would be structurally impossible not to. This link is far smaller than it was in WB4 though, so corner losses are reduced, but I don't they were completely eliminated.
I have thought of a way which corner losses could be eliminated complete, by having an open box machine with the coils outside the vessel, the vacuum vessel would need to have a pretty crazy shape though.
On pellets: If WB-mode can be achieved with gas then I agree the best idea would be to try that first as it is less complicated. If not much luck is had with that method then maybe you could try dropping a pellet of water ice (which might be easier to produce) into a ready formed electron well where the electrons are all just rattling about, like I said, putting fusion aside for the moment just to see if a stable wiffleball can be formed.
I would imagine that collisions of the high energy anisotropic streams of electrons with the pellet material itself might tend to cause them to become more isotropic in anycase. But yes, the whole thing would probably be more of a back up plan if stable wiffleball formation could not be achieved with the gas.
B=1 is when electron kinetic pressure equals magnetic pressure.
Here are the two routes as previously mentioned to achieve B=1
Constant Magnetic Field, Increase electron pressure.
And Constant electron pressure, increase magnetic field
Wow 2.5e22/m**3 is quite an impressive number. And its only going to get larger. Previously Dr Bussard impressed me with how he derived new information from known aspects of the machine, proving his equations. One such case was in his last paper.
[quote="Dr Bussard, "bussard_wb6rpt080604fnl0107.pdf""]Before running at high drive voltages, it was useful to test for electron transport in this
configuration. Since the key variable in such tests is the electron density at the machine inner edge,
and since there was no way available to measure this density directly, it was noted that the density
could be determined with precision if the machine could be run at the beta=one condition. This is
evident from the formula for plasma electron beta: Beta = (8pi)(ne)(Ei)/B^2. If run at beta=one,
with known drive voltage/energy Ei and known B field strength, the density will be uniquely
determined. The beta=one condition can be measured by PMT data, which will always peak when
the electron density reaches its maximum, which occurs only when this is achieved. Thus, if Ei is
fixed, and the B field is swept from zero to a high value, it will always pass through the beta=one
condition. At this point the density will be calculable, thus the electron transport coefficient in the
MG transport equation can be determined for this point.[/quote]
Dr Nebel I was wondering if 2.5e22/m**3 was purely theoretical or perhaps based off some of the hard data from WB6 ?
Here are the two routes as previously mentioned to achieve B=1
Constant Magnetic Field, Increase electron pressure.
And Constant electron pressure, increase magnetic field
rnebel wrote:The 2.5e22/m**3 density is what the Polywell should have on the edge, and then it hopefully goes up a few orders of magnitude as it goes into the interior. I don’t mean to imply that ion convergence isn’t important. This power density boost is what enables the Polywell to be built in small attractive unit sizes and to easily use advanced fuels.
Wow 2.5e22/m**3 is quite an impressive number. And its only going to get larger. Previously Dr Bussard impressed me with how he derived new information from known aspects of the machine, proving his equations. One such case was in his last paper.[quote="Dr Bussard, "bussard_wb6rpt080604fnl0107.pdf""]Before running at high drive voltages, it was useful to test for electron transport in this
configuration. Since the key variable in such tests is the electron density at the machine inner edge,
and since there was no way available to measure this density directly, it was noted that the density
could be determined with precision if the machine could be run at the beta=one condition. This is
evident from the formula for plasma electron beta: Beta = (8pi)(ne)(Ei)/B^2. If run at beta=one,
with known drive voltage/energy Ei and known B field strength, the density will be uniquely
determined. The beta=one condition can be measured by PMT data, which will always peak when
the electron density reaches its maximum, which occurs only when this is achieved. Thus, if Ei is
fixed, and the B field is swept from zero to a high value, it will always pass through the beta=one
condition. At this point the density will be calculable, thus the electron transport coefficient in the
MG transport equation can be determined for this point.[/quote]
Dr Nebel I was wondering if 2.5e22/m**3 was purely theoretical or perhaps based off some of the hard data from WB6 ?
Purity is Power
OK, I finally got the camera, and I got it to work (barely, but what can I expect for $30??)Keegan wrote: Dr Mike Do you feel like scanning any exerts from "Stability of a Plane Plasma-Magnetic Field Interface: Energy Principle Analysis". Sounds Good but i just dont feel like giving Amazon $117 especially if Dr Krall isn't going to see any of it.
Check out section 5.12 of Krall & Trivelpiece as a set of jpeg's. I tried them on my browser before using ftp, but noticed after I uploaded them they are just a touch too big. But some shots are blurry, so the extra data helps - it is all readable.
I'll have some more experiments in a few days - I want to upload some notes. Not sure I'll have time to type them into PDF's, so I may just take pictures of my scribbles.