Yet another, free, all magnetic idea.

[broli]

MuMetal for example?  And rather thick as the field needs to be canceled as much as possible.  Thereby the drawing with the 'rotor' mags having shielding as well may offer a better chance of exit?

MuMetal is probably way beyond anyone's budget. Plain iron or steel should be good enough. Just make sure you can confirm the field inside the tube being much weaker than outside of it if so you have a good setup.

The more I think about that drawing the less reason I see for that shield. If you shield the moving magnets you just make the overall forces much weaker. So the message is, do not shield the moving magnets.

You just made me spark an another idea. I will post it tomorrow as I'm going to sleep now.

[gravityblock]

I may be getting ahead of myself here.

Could the Halbach array be used for shielding?
What would be the advantages and disadvantages of this type of shielding?

How to build a Halbach Array:  http://www.matchrockets.com/ether/halbach.html

[ramset]

Broli
isn't mumetal on the back of old hard drive mags [salvage my favorite word]

Also for those who don't know http://sirzerp.blip.tv/#1618702

Chet

[capthook]

THE cheapest/best magnet supplier out there.
I've placed many orders with them, always A+.

http://www.magnet4less.com/index.php?cPath=2_28

3.54" OD x 1.77" ID x 0.63" thick, Grade C8, Ceramic Ring Magnet
(90mm OD x 45mm ID x 16mm thick)
$9.90 each
Grade C8
Magnetized through the Thickness 0.63"

[gravityblock]

Also for those who don't know http://sirzerp.blip.tv/#1618702

Chet

Thanks for the link.  That is awsum if the images do represent the exact dipole nature.

Keep the information flowing, now I can learn something.