Google Polywell Fusion Counter

KitemanSA · Post by **KitemanSA** » Tue Feb 10, 2009 1:44 am

MSimon wrote:28,800 for polywell fusion

15,900 for Polywell Fusion

XX
Orz

(i.e. beating my head against the floor)

Roger · Post by **Roger** » Tue Feb 10, 2009 3:05 am

Aero wrote: Of course, he didn't say where the hot spots were located in relation to the cusps.
....and the hot spots are on the coils, not the walls. While this isn't a proof, it's a pretty strong indicator.

viewtopic.php?p=16276#16276[/quote]

I had the same question. Where were the hot spots, the coil joints?

Dr Nebel didnt say, but the contract says coil joints. IF so, this points us in the direction Wb-7.1 is going to go. And the contract talks about electron temp losses, which made me think of cold electrons at/near the edge, not about electron losses. Anyway the electron temp losses were near the coil joints if I remember the wording right.

I mean for Christ sakes, if all we are talking about is re-mounting the coils to get a better WB, I mean really, if that is 1st priority at this time......

Get it done and start measuring the result.

alexjrgreen · Post by **alexjrgreen** » Tue Feb 10, 2009 9:38 am

Roger wrote:I had the same question. Where were the hot spots, the coil joints?

Dr Nebel didnt say, but the contract says coil joints. IF so, this points us in the direction Wb-7.1 is going to go. And the contract talks about electron temp losses, which made me think of cold electrons at/near the edge, not about electron losses. Anyway the electron temp losses were near the coil joints if I remember the wording right.

By coil joints, did you mean the spacers between the coils? Perhaps they're mechanically desirable but not mechanically necessary. Someone here suggested supporting the coils individually from the vacuum chamber walls: challenging to adjust but no spacers.

Or did you mean the joints where the power feeds in?

Roger · Post by **Roger** » Wed Feb 11, 2009 3:49 am

alexjrgreen wrote:

By coil joints, did you mean the spacers between the coils? Perhaps they're mechanically desirable but not mechanically necessary.

Yes, the spacers between the coils.

If WB-7 is like WB-6 then the power feeds come thru the 4 stand offs holding the bottom coil and I believe travel from coil to coil. An alternative maybe is to have standoffs from the vacuum chamber walls, as you mentioned, bringing the power to each coil separately, keeping the standoffs in the coil shadow.

KitemanSA · Post by **KitemanSA** » Wed Feb 11, 2009 4:19 am

Roger wrote: If WB-7 is like WB-6 then the power feeds come thru the 4 stand offs holding the bottom coil and I believe travel from coil to coil. An alternative maybe is to have standoffs from the vacuum chamber walls, as you mentioned, bringing the power to each coil separately, keeping the standoffs in the coil shadow.

On WB-6 and WB-7 the "spacers" are right smack-dab in the middle of the funny cusp. Talk about your not-so-good design choice.

I guess it was understandable when they were hurredly trying to build a brand new type of coil can with sweep-up money, and maybe even when simply trying to re-create the one that blew away. But no more, hunh?

Seems a pair of them about 5cm on either side of where the existing one is would be a better situation. And if the WB-8 is made with square plan-form coils as Dr. B wanted, the effect might be improved even more. After all, the funny cusp should shorten a lot with the square plan-form coil.

MSimon · Post by **MSimon** » Wed Feb 11, 2009 4:29 am

KitemanSA wrote:
Roger wrote: If WB-7 is like WB-6 then the power feeds come thru the 4 stand offs holding the bottom coil and I believe travel from coil to coil. An alternative maybe is to have standoffs from the vacuum chamber walls, as you mentioned, bringing the power to each coil separately, keeping the standoffs in the coil shadow.
On WB-6 and WB-7 the "spacers" are right smack-dab in the middle of the funny cusp. Talk about your not-so-good design choice.

I guess it was understandable when they were hurredly trying to build a brand new type of coil can with sweep-up money, and maybe even when simply trying to re-create the one that blew away. But no more, hunh?

Seems a pair of them about 5cm on either side of where the existing one is would be a better situation. And if the WB-8 is made with square plan-form coils as Dr. B wanted, the effect might be improved even more. After all, the funny cusp should shorten a lot with the square plan-form coil.

Square coils are problematic because magnetic fields want to be circular. And who knows what distortions of the magnetic fields in the center of the coil will do for you or against you?

If circular coils are giving results I'd stick with them to the point of proving the concept. After that - no worries - there will be lots of funds to try lots of things.

KitemanSA · Post by **KitemanSA** » Wed Feb 11, 2009 4:38 am

MSimon wrote: Square coils are problematic because magnetic fields want to be circular. And who knows what distortions of the magnetic fields in the center of the coil will do for you or against you?

If circular coils are giving results I'd stick with them to the point of proving the concept. After that - no worries - there will be lots of funds to try lots of things.

One problem with the current design is that the virtual corner coil is REALLY poorly shaped. It is a tri-corner star; about as far from round as it is possible to get.
And since Dr. B proposed it, I suspect he had a pretty good reason.
I have asked around to try to get someone to calculate the fields, but so far no luck.
Any suggestions? I've tried kcdodd who did that neat green bag calc, but he hasn't responded.

MSimon · Post by **MSimon** » Wed Feb 11, 2009 5:30 am

KitemanSA wrote:
MSimon wrote: Square coils are problematic because magnetic fields want to be circular. And who knows what distortions of the magnetic fields in the center of the coil will do for you or against you?

If circular coils are giving results I'd stick with them to the point of proving the concept. After that - no worries - there will be lots of funds to try lots of things.
One problem with the current design is that the virtual corner coil is REALLY poorly shaped. It is a tri-corner star; about as far from round as it is possible to get.
And since Dr. B proposed it, I suspect he had a pretty good reason.
I have asked around to try to get someone to calculate the fields, but so far no luck.
Any suggestions? I've tried kcdodd who did that neat green bag calc, but he hasn't responded.

Indrek responds from time to time. Why not give him a PM?

TallDave · Post by **TallDave** » Wed Feb 11, 2009 2:15 pm

On WB-6 and WB-7 the "spacers" are right smack-dab in the middle of the funny cusp.

I don't think so. They appear to be in the middle of the line cusps.

http://www.emc2fusion.org/

http://incontiguousbrick.files.wordpres ... mplete.jpg

There seems to be some confusion about where the cusps are and which cusps are which. There are 6 point cusps at the center of each circular group of coils. There are 8 "funny cusps" at the corners of the cube. There are line cusps along the edges of the cube.

I also just noticed looking at these that WB-7 appears to have more spacing between coils than WB-6, which is interesting.

KitemanSA · Post by **KitemanSA** » Wed Feb 11, 2009 3:51 pm

Ok, your definition is different than what I have understood to be the prevailing language. This is kind of why we need a FAQ/Glossary type section in this forum.

My take has been that the 6 coils and 8 virtual coils all produce point cusps. The idealized 4 way intersection between coils is the "funny cusp". But the circular shape of the current coil configuration makes the "funny cusp" quasi-linear.

It seems that Dr. B wanted to make the "funny cusp" less line-like by converting to square plan-form primary coils which would make the 4 way intersection more idealized.

Others?

TallDave · Post by **TallDave** » Wed Feb 11, 2009 3:59 pm

Here's Bussard on this in Valencia:

The original patent concept, which provides the basis for the
physics of this type of machine, presumed coil conductors of
zero cross-sectional radius, placed exactly along vertex
edges, with sharp corners where coils came together. This
led to an odd point/radial-line at such corners which had zero
field over zero radius. This was called a “funny cusp“ by the
very first reviewers of the concept (1987). It is, of course,
not attainable with any realistic coil conductors of finite size,
and (as discussed further below) this engineering fact has
profound and dominating consequences for the design of any
machine hoped to be useful and practical for net power
production.
***
The understanding of the effects of finite coil
dimensions on the role of the —funny cusp“ losses at
corners, and the resulting need for precise construction
at these points (see above), i.e. spacing at several gyro
radii.
***
1) Design, building and parametric testing of WB-
7 and WB-8, the final two true polyhedral coil systems, with
spaced angular corners, to reduce “funny cusp“ losses at the
not-quite-touching points, and yet provide very high B fields
with conformal coil surfaces. These would be topologically
similar to the original WB-2 and PZLx-1, but without their
excessive unshielded surface losses, and with pure
conformal coils and small intercept fractions. These latter
can be achieved by appropriate spacing between the corner
junctions (typically several gyro radii at the central field
strength between adjacent coils) to allow free circulation of
electrons and B fields through the “funny cusp“ regions,
without direct B field line impact on or intersection with the
coils themselves.

KitemanSA · Post by **KitemanSA** » Wed Feb 11, 2009 5:23 pm

Yup, looks like he and I are using the same lingo. Funny cusps in the "spaced angular corners".

MSimon · Post by **MSimon** » Wed Feb 11, 2009 6:09 pm

I still wouldn't deviate from something that is working (even poorly) to something else unless we had some money to burn to find out if "better" is really better.

KitemanSA · Post by **KitemanSA** » Wed Feb 11, 2009 10:19 pm

Isn't this sort of what the latest round of $ is all about?

MSimon · Post by **MSimon** » Wed Feb 11, 2009 10:59 pm

KitemanSA wrote:Isn't this sort of what the latest round of $ is all about?

As far I can piece together from the bits floating around - the WB-7.1 will have all the toroid coils individually supported to eliminate the tits (a technical term) between the coils.

Short of tying everything to the walls I think a frame type structure around the coils might work nicely.