Talk-Polywell.org

I'm trying to understand the conflicting messages I'm getting wrt WB7/8's configuration, and the rest of Dr. Bussard's google TechTalk.

1. My reading of the text leads me to believe that the hoop/rings will be replaced:
"but would not use circular coils, rather they will use coils that follow the polyhedral configuration..."

Yet, isn't keeping the surfaces conformal to the sphere necessary to create a spherical electric field potential? Isn't putting a charge on a surface with sharp bends which has shown a tendency towards discharge a bad idea? Won't the magnetic field lines through the center of such a facet be "unbalanced", squeezed more by the sections that are closer? That's without considering the challenge of making an irregular surface conformal to an irregular mag field in the first place....

I presume that there is a reason to desire this shape, so, if someone could explain it, I'd sure appreciate it. The expectation is that WB-7/8 would work roughly 3-5x better than WB6....

2. "There is only one configuration that works, and that is the one that we patented. It is a configuration that is a polyhedron where the coils are all on the edges of the polyhedron, and the polyhedron has the property that there are an even number of faces around every vertex so that alternate faces are N, S, N, S...."

There is only one Platonic solid that has an even number of edges per vertex, and that's an octahedron. It doesn't look remotely like it would be conformal to a sphere, although making it so would seem similar to intersecting three toroids at right angles. At anyrate, all I hear about is "truncated cube" and "truncated dodecahedron", whose Platonic solid constructions do not meet the above criteria. Is there a different construction planned? What am I missing?

[I realize this is similar to the ongoing Magrid Configuration thread, but I rather felt that conflating my novice concerns into that thread would wind up deflecting the point of that conversation. Feel free to correct if that's an unwarranted concern, though.]

TIA
-Dave

I tried working out the math of "covering a sphere with circles evenly". If you add the criteria that the circles much touch each other the same number of times, only N = 4, 6 and 12 will work. If you remove the criteria of touching, then the circles can be evenly spaced by giving each one the same solid angle: 4*PI/N. The problem is that the spacing between the centers of neighboring circles is not uniform, so you don't get a uniform field.

That may not be a problem, and in fact future designs may want non-uniform field distributions for particular reasons. For now, uniform is easy to understand and symmetry helps shrink the work on modeling.

The main reason for N=6 is symmetry and simplicity. Cubes are easy to understand

Wasn't Doc talking about WB7 being a Truncated Cube, and WB8 being a Truncated Dodec.

Hey dave, you got all the facts right. It just sounds contradictory. It is rather hard to visualize.

When the good Doctor B dreamed of WB8 it would have looked something like ....





Artwork by Tony Rusi and Skip Baker


Hope that helps

dnavas wrote:...
1. My reading of the text leads me to believe that the hoop/rings will be replaced:
"but would not use circular coils, rather they will use coils that follow the polyhedral configuration..."
...
-Dave

I haven't seen any plans to actually do that, but it might have advantages. It would also be more work to build.

My interpretation of that configuration (already had the model drawn up):

footnote: The struts between coils are placed like they are in my image to keep them out of the cusps where coils 'kiss'.

Keegan wrote:

A truncated Dodec.

The icosahedron looks very interesting. It violates one of the rules I originally started
with, but it's obviously nicely uniform. I need to think about the rules of formation a bit
more, there must be an easy way to find uniform tessilations on a sphere.

Uniform tessilations on a sphere aren't that hard, within limits. Take a look at http://www.mathpuzzle.com/Fairdice.htm. For a number of those polyhedrons, including the icosahedron, place a magnet ring on a face, field return faces on the vertices, additional cusps on the edges between kissing magnets. If tests suggest more facets is good, or you wanted to scale up but keep the same tooling for your magnets, the Pentakis Dodecahedron looks like a promising base polyhedron for 60 magnets. Various tilings for geodesic domes should work for insane facet counts.

Put a coil in the center of mass of each facet and leave room between coils for return current (circulation current I guess is a better term). Very cool!

The rule he uses is:

To be isohedral, each face must have the same relationship with all other faces, and each face must have the same relationship with the center of gravity.

That it is related to dice should be fun topic at the dinner table this weekend. My kids will be playing D&D for a long time....

Thanks!

D&D uses 4 sided on up to 20 sided dice, IIRC. ANd I have them all/