Talk-Polywell.org

So is this an acceptable support structure?



Note: Vacuum chamber is 6m wide, etc.

So is this an acceptable support structure?

I would have thought the stand-off legs would be positioned at a point rotated 45 degrees ( about coil axis) to those shown. Maybe lower electron flux there ... but no data to know for sure.

EDIT: Just remembered that it has been discussed that the stand-off legs would be more protected if they were directed on a radial line, away from the reactor core center, i.e. rather than parallel to the coil axes as you have here.

Ideally they would be on some minimal field trajectory to the wall that could be found with magnetostatic analysis once plasma topology is known.

icarus wrote:

So is this an acceptable support structure?

I would have thought the stand-off legs would be positioned at a point rotated 45 degrees ( about coil axis) to those shown. Maybe lower electron flux there ... but no data to know for sure.

Concur that the electron flux would probably be lower there than at the current nub-space; but the magnet interaction loads should be also be highest at the current nub space, no? If so, the supports being at the 45 degree point would magnify structural issues. Gotta have SOMETHING for engineers to do!

If so, the supports being at the 45 degree point would magnify structural issues.

I would have thought that at this point the physics of getting a net power reactor trumps yet to be determined 'structural issues'?

Aside from fine tuning as mentioned above, the illustration fits my understanding of the design of WB8, which I believe may resemble the picture on the second page of this presentation:

http://www.plasma.ee.kansai-u.ac.jp/iec ... ogers2.pdf

Dan Tibbets

Support structures "twisted" by 45 degrees:



Dr. Rogers illustration, to my uncalibrated eyeball, doesn't look like 45 deg. twist, but his cantilevers look proportionally much longer than those shown above.

What are the best dimensions for the vacuum chamber of a 3m diameter Polywell?

Ideally they would be on some minimal field trajectory to the wall that could be found with magnetostatic analysis once plasma topology is known.

I agree this will drive the optimization of the design. Perhaps there will be a tradeoff between complexity of engineering (invovled with following "some minimal field trajectory) and net power production that will allow for cheaper but less efficient reactors.

It seems logical to me that each coil will be supported separately for many of the reasons already discussed. Flow of coolant has been mentioned. How about flow of current? Which leg (or legs) would current flow "into" the coil and which leg (or legs) out? Does the number of turns of wire in the coil affect this decision, i.e. with more turns is there a number at which having one less wire in a segment of the coil (because the inbound and outbound currents flow through different legs) does not cause castrophic imbalances in the magnetic fields? What about the magnetic field around the legs themselves caused by the flow of the current? Do you want one? If so, in what direction?

I suspect these are questions ripe for simulation, once "we" understand what the interaction between the magrid and the plasma is. In other words, more (any) data.

"Untwisted" legs "splayed" by 30 degrees:

Why thirty degrees? A semi-reasonable compromise between non-coil material in the chamber and a purely radial line which would be nearer forty-five degrees.

Probably not anyone's favorite because of the recirculation interference.

Legs twisted 45 deg. and splayed by 30 deg.:



Why twisted and splayed? Just for fun.

I was admiring Dan Tibbets two-coil and decided to elaborate (or ruin if you prefer). Four-coil semi-meridian:



The usual notes. If I redid this today, I'd probably show polar entry/exit for structure, cooling and current. Though I'd have to choose between keeping each circuit integral (i.e. only one pole has entry and exit for each loop) or splitting each loop (N and S poles have exit and entry for half loops).

Sources of inspiration are funny. I was sitting with my father-in-law, watching one of the few (american) football games I watch during the year, and looked at the star on the side of the Dallas Cowboy player's helmet...and got this:



I call it interdigitation.

How about a dual-coil spherized octahedron?


And here I thought I was running out of ideas.

rjaypeters wrote:How about a dual-coil spherized octahedron?

WHY? If the currents run opposite, there is no field, if they run the same, the effect is the same as with one coil. So... why?

icarus wrote:

If so, the supports being at the 45 degree point would magnify structural issues.

I would have thought that at this point the physics of getting a net power reactor trumps yet to be determined 'structural issues'?

I would have thought that playing with legs would have little to do with "the physics of getting a net power reactor" but having one fail due to incompetent structural design would be a real slap in the face. Opinions are like...

kitebait:

I would have thought that playing with legs would have little to do with "the physics of getting a net power reactor"..... and then the bait ...." Opinions are like ....

... seeing as you are well-prepared to go down this route anyway .... and what the hell would you know about "the physics of getting a net power reactor?

Satisfied, is that the bite you were looking for? How big is your opinion?

See we can both bait but where did it get you in the end?