thread for segments files and parameters for simulation runs

happyjack27 · Post by **happyjack27** » Wed Nov 24, 2010 11:34 pm

TallDave wrote: Do we agree potential wells have been measured?

i've seen the charts in the google video. i'm curious how do they measure that? do they like shoot a tuned laser through and do some calulation based on color change or something?

TallDave · Post by **TallDave** » Wed Nov 24, 2010 11:37 pm

Yes, laser flouroscopy was used in Japan. I have a link somewhere...

Not sure what EMC2 is using. Rick may have said at some point. He did say density was not directly measured in WB-6.

happyjack27 · Post by **happyjack27** » Thu Nov 25, 2010 12:10 am

what's the signifance of the positive charge on the magrid? i don't have my static efields modeled correctly yet so i have the turned way down. but that doesn't seem to be adversely affecting wb formation.

also w/my new logarithmic sliders i'm seeing how deep a well i can get at practical field strengths on a 3m coil radius machine. at a field strength of about 10E7.45 ampturns, which i believe is in the multi-tesla range, i can get a well depth of around 10E-7.73 coloumbs before the WB starts to rupture. as i understand it that's less than ideal for D-T fusion energies. uploading the video now.

TallDave · Post by **TallDave** » Thu Nov 25, 2010 12:15 am

Ah, that might be why your electron guns have to be so finely calibrated to get electrons inside. I think the consensus here, fwiw, was that the electrons are attracted to the anode Magrid on injection.

So they're injected a bit outside the Magrid, they see it, head toward it, miss, and get stuck inside the WB.

Some think that's the main purpose of the Magrid. OTOH, Joel's simulation seems to show that the charge on the Magrid also counterbalances an electron-only plasma around the exterior of the Magrid, allowing us to keep nearly all the ions confined inside.

happyjack27 · Post by **happyjack27** » Thu Nov 25, 2010 12:23 am

TallDave wrote:Ah, that might be why your electron guns have to be so finely calibrated to get electrons inside. I think the consensus here, fwiw, was that the electrons are attracted to the anode Magrid on injection.

So they're injected a bit outside the Magrid, they see it, head toward it, miss, and get stuck inside the WB.

Some think that's the main purpose of the Magrid. OTOH, Joel's simulation seems to show that the charge on the Magrid counterbalances an electron-only plasma around the exterior of the Magrid, allowing us to keep all the ions confined inside.

oh, i had them turned on when i was trying to fire electrons from outside. though i have no idea if they were even in the right ballpark on field strength. (i have a better idea now). i just don't know if that's their only purpose or not. is it neccessarily wrong to have it off if i'm not shooting in electrons and ions from outside?

i was thinking that - that the charge might make an electron WB more spherical, as it's the same surface as the b-fields, but it's pulling instead of pushing. by the same token then it would seem that would make an ion WB less spherical.

krenshala · Post by **krenshala** » Thu Nov 25, 2010 12:25 am

happyjack27 wrote:
krenshala wrote: What I think would be an interested thing to check, and I believe would help with what you guys are talking about above, would be to start the sim with zero electrons "in the system" and the magrid active, then power up the e-guns and slowly start shooting electrons into the well.

This should test both whether you can get enough electrons into the system with the guns outside the magrid (firing into/through cusps), but it should also be another good way to verify whether they will spontaneously form that electron shell/sphere near the center.
no way vary the particle count right now. (though you can vary how many real particles each one represents) that would take some deep re-coding and possibly hurt performance. but you can start them all of in no man's land and they'll cycle through the eguns when they go out of bounds.

You could do random throughout the entire volume (in- and outside the magrid/well).

happyjack27 wrote:anycase, that's something i plan to do but in order to do it i need to calculate how much energy i need to fire them off at to get them into the wiffleball. you can see at the end of the video you're referring to i was trying to do that manually and it was just too sensitive.

until then there's really only two useful well-capable modes: start them off randomly throughout the magrid, or randomly inside WB.

What if you set it up to automatically decrease the "firing" energy of the e-guns, have it display the current energy level and have it start high and work down. You monitor the results, and when it starts bouncing the electrons out instead of letting them in, note the current energy and start again with a slower change over a smaller range ... (i.e., this sounds like a case for iterative testing. :/ ).

happyjack27 wrote:having posted the exe yet. it's constantly evolving ...

at minimum you need a CUDA-capable card. Which means we're talking Nvidia processor GeForce series. ... i'm not sure but i think you need some library files so you might need to download the nvidia sdk. but maybe i can find hot to turn them into static libraries so they're compiled into the exe. tell you what i'll compile a 32-bit version and a 64-bit version and upload both. but you might not see it till after thanksgiving.

I've got an (only OK) integrated 8200 on the motherboard, and a PCI-E GTX205 (iirc) in the system i've been neglecting to reinstall the OS. The other system has a 9800 GTX, and the motherboard in that system is capable of SLI (and I've got an appropriate PSU for it, too), so I know I can run it, just not necessarily as easily as you can.

I'll have to look into the SDK. The system is going to be dual-boot XP/Gentoo-64 so I know I'll be able to get things working in at least one of the two environments ... if I can find the time.

TallDave · Post by **TallDave** » Thu Nov 25, 2010 12:26 am

Well, it would reflect reality less well

Joel's simulation seems to argue it would matter a lot, but it might be interesting to see what other models find.

Hmmm... is this a valid excuse to buy a new video card? I wonder if my Alienware PC can SLI two new NVidias? The 5700s just barely fit. I know the PSU can handle it. I probably should have gone for the new chipset though.

happyjack27 · Post by **happyjack27** » Thu Nov 25, 2010 12:36 am

krenshala wrote: I've got an (only OK) integrated 8200 on the motherboard, and a PCI-E GTX205 (iirc) in the system i've been neglecting to reinstall the OS. The other system has a 9800 GTX, and the motherboard in that system is capable of SLI (and I've got an appropriate PSU for it, too), so I know I can run it, just not necessarily as easily as you can.

I'll have to look into the SDK. The system is going to be dual-boot XP/Gentoo-64 so I know I'll be able to get things working in at least one of the two environments ... if I can find the time.

either one will do just fine. it'll automatically adjust the particle count relative to the gpu's core count. but if clock speeds and/or instruction throuhput per clock is worse you still might see reduced framerates. if all else fails you can halve the particle count. since it's an n^2 algorithm that should give you more fps than you could care for. currently that would require a recompile though. it'd be nice to see someone else experimenting with it.

icarus · Post by **icarus** » Thu Nov 25, 2010 12:46 am

I:

1) Can we all agree that the electric potential in the precise center is always zero? (By Gauss theorem and assuming all possible surrounding charge distributions are spherical enough)

2) Can we also all agree that the first spatial (radial) derivative of the electric potential in the precise center is also zero (i.e., either a local maxima or minima)?

dave:

Oh good, we're going to be civil now.

Do we agree potential wells have been measured?

... just stop being a know-it-all smart-ass and I can be civil. If you want to answer the question, just do so ... I'll take you answer as an "I don't have a clue".

It was nothing about what was measured it is purely a theoretic logical argument.

Anybody else want to have crack at it?

happyjack27 · Post by **happyjack27** » Thu Nov 25, 2010 1:11 am

new video, thanks to my new logarithmic sliders, pushing the well depth on a 3m wb-6. got it to about -10E-7 coloumbs space charge before the WB started to really accelerate leakage ran the mag field at about 10E-7.45 amp-turns.

http://upload.youtube.com/my_videos_upload

happyjack27 · Post by **happyjack27** » Thu Nov 25, 2010 1:23 am

just for kicks:

1 billion amp turns. a full coloumb of space charge. (that's about 10^19 virtual electrons)

http://www.youtube.com/watch?v=FUFWqjAkymI

KitemanSA · Post by **KitemanSA** » Thu Nov 25, 2010 2:36 am

happyjack27 wrote:what's the signifance of the positive charge on the magrid?

First, it is the motive force for the electron "gun" shooting into the MaGrid. Second, it restrains and returns electrons that leak out of the MaGrid to reduce losses. Third, it allows upscattered electrons to reach the chamber walls, removing them from the system, and keeping the system somewhat non-Maxwellian. At least that is what I have gleaned.

TallDave · Post by **TallDave** » Thu Nov 25, 2010 4:01 am

icarus,

I can see I'm not getting through with my concerns on civility. As you've repeatedly explained how you're smarter than the rest of us, I'm not sure why this point continues to elude you. Let me try responding in something more approximating your native tongue and see if you can spot the change in communication style.

Answering your questions was as easy as it was pointless, but you're a complete idiot and an utter jackass besides, and so I didn't bother wasting my time on such irrelevant horseshit as you choose to regurgitate onto my path but instead stepped around the nauseating piles to something that actually has some bearing on the question at hand. The force at the precise center doesn't matter, dumbass, as any fool can see. The well has been measured (you know, science? actual experiment? hello, do those ring a bell? maybe you could look them up) , which, as you would understand if you didn't have the intellect of an artichoke, negates both the ridiculously stupid, irrelevant questions you have attempted to waste my time with. You see, retard, the electrons cannot sit at the precise center for any appreciable length of time, especially given all that's going on around them. Furthermore, my dimwitted dunce, the original question was whether electrons at the middle would eventually maxwellianize (is that word too big for you?) and if you think they're going to sit there forever in defiance of all known physics as well as the common sense exhibited by most household pets we should burn down any school you've ever been near and purge your genes from the Earth for the sake of humanity.

Did that help?

Anyways... I suppose one can calculate for a given well depth and density how long an electron might be able to stay balanced at the precise center or approximation thereof, at near-zero velocity, not being bumped off-center by anything else, if one really wants to. If someone wants to calculate for what proportion and what length of time electrons can be expected to do so I will tip my hat to them, but meanwhile I'm comfortable assuming that it's small enough to ignore, and therefore electrons will tend to bounce around and maxwellianize, such that the ones at low velocity and low potential do need to be cleaned up.

icarus · Post by **icarus** » Thu Nov 25, 2010 4:34 am

Wow, didn't know you cared so much ... your tirade is quite sad though.

Who said anything about balancing electrons at the very center? Just concentrate on the literal question and try not to let pre-conceived notions cloud you thought-processes.

It is adequate to consider only cold electrons on the surface of some arbitrarily small sphere, radius epsilon, concentric with very center and take it in increasing radii shells from there. Under this assumption, at the very center the electric potential and it first radial derivative must be zero ... would you agree?

Doesn't anyone else see this, it seems blindly obvious?

It seems like a stake in ground for building a viable model.

TallDave · Post by **TallDave** » Thu Nov 25, 2010 4:43 am

Wow, didn't know you cared so much ... your tirade is quite sad though.

Indeed it is! To illustrate that notion was precisely the point of my banter, as you call it. I knew you could get it.

Under this assumption, at the very center the electric potential and it first radial derivative must be zero ... would you agree?

Yes. Again, though, I'm not sure why you think that matters. If you're really just bringing up "purely theoretic logical arguments" for no particular reason, totally unconnected to the simulation or the potential hill you seemed to question the existence of, then by all means let me stand corrected for my false assumption that this had something to do with actual conditions in a PW.