Aeronaut - 06 November 2010 02:14 PM

Brian H - 06 November 2010 09:52 AM

Is it necessary to get to the level of detail of segments of the coil for this short demo?  It might be more a distraction than anything; it certainly isn’t core to comprehending the process.

Yes, since he’s using it to teach himself as well as others. Whether it ends up in the animation remains to be seen. In any event, the lack of voiceovers is a recurring weak spot in our animations.

errrrrr…. if multiple coils are to be considered part of the learning process then that would seem to imply that we are already sure about that much regarding the structure of the alpha recovery system. .. are we?

Not objecting to the concept but this would seem to be what Rezwan just referred to as “Phase 2” stuff…

and for vansig… now with free ersatz ion beam!

Great assist, Zap! That’s close enough to get tinkerers wondering if they could build one or more of those coils profitably

would the coils not be larger as you move away from the chamber? since the wavelength of the beam’s residual kinetic energy is longer, and the horizontal position more uncertain, both diameters should increase as you move out. let’s make the 2nd one twice the diameters of the first, and the third one twice again. like the bell of a horn.

oh, and there’s no wire running through the centre of each coil. (that region is reserved for magnetic field storage).

I’ve been studying how to make high-frequency, high-current coils, and have concluded that at the necessary frequencies, skin effect of the coil conductors comes into play. At 1GHz, skin depth is 2µm, and AWG-0 copper wire has an effective resistance of 318 ohms/m, much too great for a high Q coil. so instead of solid wires, they’d be either hollow pipes or pressed flat, like a Slinky toy. I’ve been told that a strip line, with thickness less than twice the skin-depth, will not suffer from skin effect. Geometry constraints then lead this to look like the conductor is occupying the space in-between the pieces of a shrimp plate. hope that’s clear. it might be necessary to reduce the inter-loop capacitance, or find a good way to take advantage of that.

Based on inductance calculations, the first coil might have as few as five turns; each additional coil would double that

Take a look at the cutaway image used on the left of the page header for the LPP site. It shows the coil, and it seems to be somewhat expanded towards the end.  See below, original and expanded sizes.

as drawn, that looks to me like it’s in perspective.

this is more representative of the shape i’m thinking of. notice, the conductors are flat, and aligned radially to the axis of the beam:

zapkitty - 06 November 2010 07:06 PM

errrrrr…. if multiple coils are to be considered part of the learning process then that would seem to imply that we are already sure about that much regarding the structure of the alpha recovery system. .. are we?

Thus far I have only scratched the surface of the design criteria.  The coil designs need to be modeled with a magnetics simulator to hammer out number of coils, number of turns, number of windings per coil, wire diameters, etc. Particularly, the question of whether this transformer would benefit from a high-permeability, low-reluctance core has not been studied at all. It is possible that it is not necessary to keep the coil inductance down to nanohenry range, since the production reactor will be doing ~1 k shots/s.

I am pretty sure that each coil must be high quality, implying very low series-resistance, implying fat wires, or possibly even superconducting. I am expecting that it will be high voltage, relatively low current, in comparison to the input pulse. (ie: megavolts), but not certain.

Electrical engineers assure me that transformer coils are regularly >95% efficient. But they warn that, to design a transformer without solid understanding of the physics will fail. We will probably end up running thousands of simulations before construction. And maybe make small-scale mock-ups.

I wasn’t able to figure out how to make the coil formula work in the program. It did revive some memory banks in my head regarding Trig. however, which is a good exercise for me to do. I’ll leave it up to you expert engineers to finalize the details on the coil configuration. In the mean time here’s where I’ve gotten to with all your input:

Animation 3

One thing I realize is that the plasma I made is torus shaped instead of umbrella shaped as in other animations on this site. What is more accurate as the plasma runs up the electrodes?

benf - 22 November 2010 01:13 AM

One thing I realize is that the plasma I made is torus shaped instead of umbrella shaped as in other animations on this site. What is more accurate as the plasma runs up the electrodes?

... more akin to the arc of a Jacob’s Ladder or a railgun but in 2D instead of 1d so more like a sheet than a torus…

I don’t want any mystery about the dimensions we are currently using—cathode circle radius is 5 cm, anode radius is 2.8 cm and the hole is radius 1.4 cm. Wouldn’t it be best to collaborate with Torulf at some point—who made our existing animation?

Thanks for the specifications Eric. Yes it would be a good idea to join up with Torulf to develop the animations.

Collaboration is fine if you can coordinate it.  Otherwise, finding your own style and vision is very important.  The spirit of experiment is exemplified here : )

And once you get comfortable with this, what would also be great is animation that shows how the various instruments gather their data.  If you can build those on…what a nightmare for the animator!  But how illuminating for the viewer.  That’s where collaboration might be useful.  Divide the load.  Do a core build and send that out, and each collaborator adds an “instrument” segment…

Yes, I’ve been thinking along these lines, but am not sure how to make the process happen with other people. To start with, any other specifications that are considered vital should be made known. I don’t have a CAD background so not every detail may show up accurately, though I’ll try my best. There isn’t a “Generate Plasmoid” button in my program. I don’t have the math skills at this point to make it happen by formula. I can approximate and further enhance in Photoshop, however….Animators that have the engineering skills and better software can develop the parts that are more daunting. And those of us with the art backgrounds can supply ideas to make illustrations have more appeal (or not, lol!). In the end you’ll have eye catching products that hopefully capture the public’s interest. I also don’t have voice over abilities, but I could send the animation clips to you all on disc and you can arrange them however you want with voice overs, music, graphics from a variety of sources. I’m happy to work with others and help move things forward.