Talk-Polywell.org

KitemanSA wrote:So, 2+ years into the 4 years and all we got is a website with an old, useless video?

Did anyone expct anything different?

It's Lockheed, so if I ever did, I definitely shouldn't have

Did they say WHEN the 4 year countdown would start? "We expect a working fusion reactor in 4 years (starting to count as soon as we reach breakeven in our lab)"


Or maybe, they are counting it from the reference frame of the electrons in their machinery, which moving near light speed in the electron clouds of the atoms, experienced just a few seconds since the announcement

My sense is they have a ways to go. In general, it would seem that they have some money and bodies are are pressing ahead. No matter the outcome, it will at a minimum add to the body of knowledge, and that is a good thing.

"A working fusion reactor" is a very vague label and could mean almost anything. A substantial number of amateur fusioneers have built working fusion reactors. If some deuterium is fused with reasonable measurements to confirm it, you have reached this goal. Adding qualifies is what makes things more interesting and makes the promises more challenging. Terms like breakeven, profitable fusion, deployable fusion, steady state or useful pulsed operation, engineering challenges to make the entire system viable, etc.....

EMC2 has demonstrated deep potential wells (though there currently seems to be some backtracking on this issue), high Beta electron containment, and other issues. There does seem to be a schism between current EMC2 thinking- deemphasizing recirculation, while the Lockheed design embraces it to the point of comparing it to a FRC type of plasma flow (at least a subset of the plasma).

The achievement of targets are open to interpretation, and even the targets themselves may vary, depending on who you are talking to.

Another way of making my point is that parts are parts, but until a complete system is assembled, you do not have a chicken.

Dan Tibbets

Surely now that Park has proven Grad's conjecture on cusp containment, Lockheed will put that knowledge to use. Recirculation should no longer be needed, and why wouldn't Lockheed join with EMC2 and push forward???? Makes no sense to me.

Would that not present a control of IP issue for Dr. Park?
I suppose at the end of the day, if EMC2 has no viable path forward, then partnering with Lockheed could be an option.

I think they've already worked together to some extent.

Dr. Park has expressed a surprisingly non-competitive attitude about fusion to me. His ideas are protected by patents, and would be defended, but he told me it is OK if one of the other outfits get there first, and would be pleased if his work helped make it so. This is not a one-firm-succeeds, the rest fail situation. If one firm succeeds, fusion physicists will have plenty of work making it practical.

Which should not, in any way, be interpreted as him not thinking EMC2 is way ahead in the hunt at this point.

Okay, I admit trying to be obtuse... I do know what is going on, and will not comment.

I agree Tom, as I understand, EMC2 does not hold competitive concerns about other efforts. That is just not the way Jaeyoung thinks.
If anything, he would be happy to see someone succeed. Now whether or not he thinks they have a good or poor chance is entirely another discussion that I am not going to enter.

mvanwink5 wrote:Surely now that Park has proven Grad's conjecture on cusp containment, Lockheed will put that knowledge to use. Recirculation should no longer be needed, and why wouldn't Lockheed join with EMC2 and push forward???? Makes no sense to me.

Adequate high Beta containment applies only to electrons. In the Polywell a deep potential well is assumed. This electrostatically contains the ions. The cusp hole size is at best one gyroradius wide. For an electron this is a relatively small hole relative to the total surface area of the containment 'sphere' For ions this hole size is at least 60 times wider and 360 times more area. This is why having only intermediate deep potential well depth (relative to electron injection energy, may be problamatical for the Polywell. Additional heating of the ions by neutral beams, microwaves, etc could push the ion energies above the potential well and electrostatic containment would not dominate for the ions.

In the Lockheed design there is no claims made of ion containment by a potential well. As such even high Beta cusps would leak ions excessively. This is why recirculation between cusps is an integral part of the design.

Dan Tibbets

We know Lockheed's magnet struts are big trouble, rapid cusp plugging to reach high beta is essential, and recirculation then makes no sense. After that Lockheed becomes another version of Polywell...

In the Lockheed design there is no claims made of ion containment by a potential well. As such even high Beta cusps would leak ions excessively. This is why recirculation between cusps is an integral part of the design.

Electron recirculation is one thing, imagine ion recirculation and strut heating, or hot ions blasting metal off the struts! Am I missing something?

In the Polywell a deep potential well is assumed

No, it is not. Is a requirement. This is the next test...

The ability to drive the well is the point of conjecture.

mvanwink5 wrote:

In the Lockheed design there is no claims made of ion containment by a potential well. As such even high Beta cusps would leak ions excessively. This is why recirculation between cusps is an integral part of the design.

Electron recirculation is one thing, imagine ion recirculation and strut heating, or hot ions blasting metal off the struts! Am I missing something?

Yes. At east in an optimist view. Structures like struts are magnetically shielded and perhaps also electrostatically shielded (at least of one species- like ions). This shielding is not part of the containment- cusp confinement, it is different,and the challenge would be to incorporate it without interfering unduly with cusps confinement and/ or recirculation.


Dan Tibbets

mvanwink5 wrote:We know Lockheed's magnet struts are big trouble, rapid cusp plugging to reach high beta is essential, and recirculation then makes no sense. After that Lockheed becomes another version of Polywell...

Again the use of the term of cusp plugging. I do not like the use of this term in this situation and this is not what happens (my understanding) with high Beta. The cusps themselves are essentially unchanged at the magnet midplane radius from the center. It is the throat of the cusps that are flattened out so that the ratio of the total surface area versus the leakage surface area is greatly diminished- the funnel analogy. It is not a pinch- so a view of cusp plugging by squeezing the cusp closed is inappropriate. 'Rapid cusp plugging' is not essential. Lacking adequate electron injection power (which is apparently considerable) to build from low to high Beta does require this startup work around though.

Electrostatic cusp plugging is an often mentioned method of decreasing cusp leakage, and it apparently works well for various machines (like WB5). But, this results in undue influence on the oppositely charged species (positive ions). It competes with the central potential well and ion electrostatic confinement is harmed. My limited understanding is that Dr Parks considers the positively charged magrids as causing too much cusp plugging as the exiting electrons are slowed and reversed once mildly outside the midplane radius of the magrids . Any benifits of improved electron electrostatic containment/ recirculation is more than off set by decreased ion electrostatic confinement (different in details, but essentially like WB5). A cusp plug is a local collection of like charge that repels the mobile charged particles of interest. Of course this has the opposite effect on oppositely charged mobile particles. I think Bussard may have felt that this turn around distance for same cusp recirculating electrons was far enough outside, but perhaps further experiments have disproved this. I personally believe that there may be some modifiers that might be beneficial (in my expert openion ).

As per Dr Parks comments, same cusp recirculation of electrons is harmful (loss of potential well in corner cusps), and manipulating external conditions so that neighboring cusp electron recirculation ocdcurs is of minimal benefit. He estimated a two fold improvement at best. This seems at odds with Dr McGuires (sp?) vision of neighboring cusp recirculation of neutral plasma overcoming the intolerable magnetic ion cusp containment, even at high Beta.

Dan Tibbets

ladajo wrote:

In the Polywell a deep potential well is assumed

No, it is not. Is a requirement. This is the next test...

The ability to drive the well is the point of conjecture.

I meant that if you assume ion electrostatic confinement, you require a deep (what ever you definition of deep is) potential well. Dr Bussard used 80%. Dr Parks suggests that 50% may be a more realistic goal (at densities of interest?). Of course, as pointed out by Dr Krall in one of the 1990s papers, it is expected to become more difficult to drive to a deep potential well as the density is increased due to simple conservation of energy principles.

Dan Tibbets