Hi from North Carolina

Post here once you join, and tell us about yourself so we have a clue who we are talking to.
Keep threads short here -- once you have something to say, there's a topic here somplace where it will fit -- and if not, let me know and I will make subforums as necessary. We want all of hard science and tech up here, and if something doesn't fit -- that's my fault and I will fix that for you. See the rules and tips in the parent forum, please.
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This sub forum is for new menbers to announce themselves. Try not to create long threads here -- this is just for you to tell us who you are, and for us to say welcome. There are other forums to actually discuss real tech-science things here, and ask questions on. The idea hopefully is to have enough forums and subforums that nothing sci-tech related will be off-topic, there will be a place for it. If I missed something -- let me know, and I'll fix that.

Hi from North Carolina

Postby csnyder » Thu Feb 03, 2011 3:05 pm

I feel some questions bubbling up so I would like to introduce myself.

I am 47, educated as an electronics technician, currently employed as a programmer and build/fly ultralights/light aircraft.

I have the desire to fiddle with plasmas - who knows where that may lead. I realize "fiddle" is not a lofty goal or scientific term but accurate for a noobie.

Thanks to all who contribute here and to Doug Coulter for the ongoing effort to maintain this forum.

This is a repeat of my introduction in the Fusor Forum. Its great to have both boards as a resource.

Charles
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Re: Hi from North Carolina

Postby Doug Coulter » Thu Feb 03, 2011 3:40 pm

Welcome! We are sort of attempting to "write the book" on plasmas and a few other things, but you know what? It takes questions to stimulate those with the knowledge to go ahead and write it down, sometimes. While we don't really have a subforum for Q&A yet (but who knows), we should have nearly enough forums so any questions can kind of go in the right category, and if not, let me know so I can create the right place. Since our search stinks (no help on that one yet) I am trying to keep things as organized and on-topic as possible, so people can find the already-answered questions easily.

I bet BillF wants to fly your plane...
Posting as just me, not as the forum owner. Everything I say is "in my opinion" and YMMV -- which should go for everyone without saying.
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Re: Hi from North Carolina

Postby Joe Jarski » Thu Feb 03, 2011 7:47 pm

Hi Charles, I have a few airplane projects myself, although recently I haven't been much of a builder or flyer - I'm more of a plasma fiddler at the moment. I started out with a simple goal of doing a little sputtering and got sucked in. I still don't know where it's leading me, but it's all fun stuff. Welcome!
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Re: Hi from North Carolina

Postby Bill Fain » Thu Feb 03, 2011 8:55 pm

Charles,Hi. Welcome aboard. Glad to have another person interested in fusors living close by (about 90 minutes). I'm not conversant in ultra- lights so I put a few words into Google. Your photo looks like a mini RV6, so I put that in with ultra lights and came up with this http://pfranc.com/projects/turbine/rotax/flt24-RV6/ as one of the hits. Although not exactly what I was looking for, I thought it was a pretty neat site. I used to fly an Aeronca Champ when I was a teenager, but am sitting out my medical for a little while, in hopes of getting back into active flying again this summer. Hopefully we can meet in person soon. -bill
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Re: Hi from North Carolina

Postby csnyder » Fri Feb 04, 2011 9:49 am

All, thanks for the welcome.

Joe - As you know from the aviation community, there are talkers and builders. IMO, the worst builder knows much more than the smartest talker - I want to be a builder in the plasma community also. I like to use the reality of flying to clear my head when the ion tracks get too fuzzy. Maybe you can do the same when the weather moderates up your way :)

Bill - The plane is a Hummel Ultracruiser - here is my build website if your interested http://cwsnyder2001.blogspot.com. The plane has the potential to meet the ultralight aircraft requirements but came in a few lbs overweight. I am in the process of registering it amateur-built experimental and I will use my private pilot certificte as a sport pilot so that i can skip the physical. Maybe I can make a trip your way.

I feel like building the "standard fusor", while educational, would be reinventing the wheel (like designing another airplane). I hope to get the required equipment and environment for plasma creation and work on efficient fusion (I believe that's the jist of Dougs work and why I follow his progress.) .

Again, thanks for the welcome.
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Re: Hi from North Carolina

Postby Doug Coulter » Fri Feb 04, 2011 10:04 am

I think that talker vs builder thing is right on the money, and in fact is why this site is here (at least in my mind). Note our "talker section" which is the water cooler, auto-deletes threads that go idle for just that reason. Everybody like to talk, it's inevitable, but there's no need to corrupt all the other stuff here that is timeless with it. If we had a better search function, maybe that would be different, but I'm trying to keep the actual content separate from "gee whiz, how's the weather where you are?". So far, it's mostly working. If we get a flood of newbs, we'll restrict them to sections like that till they build something and actually have something to say worth listening to.

I have to just go and mow the lawn or shoot up things in the back yard when I need escape from the lab -- no planes, but I once fell in love with an ultralight version of a Vari-Viggen -- that could use my yard as a strip I think, a real hot rod. It'd be a little like that mountainside stall-landing in "Air America" though, unless I got some bulldozing done.

Building a standard fusor....well, that's pretty educational too, and requires all the same foundations, skills, and parts that something more advanced needs; as far as I know now, they all need the same parts of the "elephant stew" as the base for the recipe, so I don't put that kind of thing down, and am rooting for the Tech guys, for example -- you gotta start somewhere.

But having done it, and learning the limitations via bothering to do some measurements no one else seems to bother with, I'm ready to move on to something more myself. Frankly, I'm glad I got all this other experience under my belt, because I think it's helping -- more understanding of the issues, more confidence that something I propose might handle some of them well, and so on.
Posting as just me, not as the forum owner. Everything I say is "in my opinion" and YMMV -- which should go for everyone without saying.
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Re: Hi from North Carolina

Postby Doug Coulter » Fri Feb 04, 2011 1:46 pm

Charles, if you're interested in the alternate approaches I am currently looking at, the big deal that got me going was posted here:
viewtopic.php?f=9&t=58

Which in turn inspired the fusor II speculation here.
That's mainly a way to do on purpose what a couple of setups here seem to do a little of by accident, more or less.

But lets discuss that scope shot in the first link. Anyone who can actually explain various parts of that correctly is probably in line for some kind of award, because there are a few things going on that simply don't make a lot of sense, yet they happen, are repeatable, and lead to huge Q increases.
Here's the image again.
SyncPulses.jpg
Reposted image, neutron detector on top, voltage on second grid bottom trace
SyncPulses.jpg (25.69 KiB) Viewed 5393 times

The upper trace is AC coupled, which is why the first couple of pulses don't show correctly till they charge the cap in the audio amp the scope was hooked to. Oops. But that's not enough to wreck the analysis value here.

This is in a two grid setup. At the gas pressure I was running, the main grid can have 50kv on it and draw basically zero current -- it's past the Paschen's law light off point. But even a smaller voltage on the second grid (see the picture/movie at the link) will light off and make ions at that point (which "turns on" the main grid too), due probably to it being able to "see" much longer path lengths out in the main tank area. Note, we had already seen some "interesting things" in various free running pulse modes earlier, and this experiment was partly an attempt do do on purpose what we'd seen by accident with various conditions before -- and to do it the easiest, dumbest way to get a feel for things.

So, for this, the 2nd grid (which BTW is not shaped right to make neutrons, never makes many at all under any conditions) is tied to one leg of a neon sign transformer through a coupling capacitor. Note that we have a rectifier -- when the grid attempts to go positive, all the free electrons in the tank head that way and draw current. One of the huge questions though -- why in the world does that take milliseconds -- see that overshoot? It's real. All the theories I know on charged particles indicate that microseconds should be more than enough time, but yet we see what we see here. Secondly, during the negative half cycle, we see these pulses in the grid voltage (the NST is a pretty high impedance) that go well above ground, while the NST is trying to push it negative -- they can't be much current though, because they don't discharge the cap -- note after a pulse a return to the NST basic waveform. Further, and this is of course the interesting part - note when the neutron detector (3He tube), fires. Also note the timings -- you see a jump down in the waveform with some overshoot when the NST polarity flips -- then some time where nothing happens, even though the volts are fairly high (negative) then some pulses at a rate that's pretty slow compared to any reasonably calculated particle transit times.

Now I have a kind of half formed set of notions in my head on some of the whys here -- but to me, this is the most significant thing my lab has yet produced, and it's replicable as can be. The free run version is not so much so, but it did show us record setting neutron outputs and out of this world Q figures, as in that case, the main power current was a mere .1 ma -- the lowest the digital meter can even read! So in truth we don't really know what it was drawing -- most of that could have been corona loss or meter error for all we know now.
(we got the other pulse mode BTW with an inductor in the ballast, that resonated with the tank/grid system at about 1.8 mhz)

One big question -- do we need to sweep the electrons out first, every time? Maybe not, since we get multiple fusion pulses after each sweep here.
Second -- why does that take so long?
Third -- why does it then "free run" at about 2 khz? Can I make that go much faster with the correct drives?

One of my notions is that stable fusor operation in the normal mode is what a math guy would call an attractor -- it's a dip in the energy surface that "attracts" the most stable operation. But, it's not the best place to make fusion -- from what I can tell, it's nearly the worst, actually, but just off that -- it gets really good. Trying to balance the thing in a steady state off the local attractor seems as pointless as trying to stand a pencil on end on the desk. You might do it with servos, but the case is such that any perturbation -- or initial error, makes it fall.

So far, just about everything we've tried that perturbs a fusor off this attractor makes it better, which leads to yet another question - can we design a perturbation that is best for fusion, and if so, what do we need to learn to know how to do that?

The fusor II link is an attempt to think about that one a little harder. Not sure that's exactly what will do the job, but it's something reasonable to try I think, and along with all the other things on my plate, I've been building out the gear to make that attempt possible.

A regular fusor seems at best to be a dimly smoldering fire -- it seems that any poking we do with any stick makes it burst into flame. I got tired of that other place because no one would even think of trying this sort of thing there (even though it's disgustingly easy to try), so they became useless to my efforts here.

Some seem to avoid any measurements that might upset their pre-conceived notions, they have too much ego invested in those notions, I guess. I'm the other way around -- I like surprises like this! I deliberately do some off the wall "cowboy science" just to see what I see, and I'm trying to do that old "expect the unexpected" or at least notice and analyze it when it happens. Seems to be the way forward.
Posting as just me, not as the forum owner. Everything I say is "in my opinion" and YMMV -- which should go for everyone without saying.
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Re: Hi from North Carolina

Postby csnyder » Sun Feb 06, 2011 11:40 am

Doug,

This is probably too many entries on an intro but still introductory so...

I understand what you are describing about the waveforms and their implications in the prior reply. Unfortunately I can not add anything of value at this time. What I take away from it is that you feel the fusor (in some form) still has possibilites that have not been explored. Looking back in the archives of the Fusor Forum, there was a lot of enthusiam that seems to be missing or squelched now. Being a determined mechanic is the first hurdle for building a fusor. After that hurdle is overcome, I think a different mindset has to takeover. Your enthusiam and insight has been inspirational. (I will not be sending donations just yet). I will leave off the rest of my philosphy.

2 items I would like your views on (or anyone's views here)

1) LDX fusion - I dislike overly complicated, job security type devices - IMO, the space shuttle, tokamaks and car engines :) - OK, noone get upset with my list, I understand some things will always be complicated. The LDX device pros and cons seemed reasonable and it appeared they were making steady, if slow, progress. There have been no updates since Jan 10, 2010. I have even toyed with building a water cooled electromagnet and trying ECRH. (I have done simulation with femm for the field strength and calculated the freq for where I want to heat the field - probably don't understand all that I know :) )

2) My starter "glow" system -

Pump - Welch 1402 (quiet, cheap/easy to overhaul, good cfm)
Chamber - Quartz dome 15" (on EBAY for now, understand the risk of localized heating implosion, shielding requirements etc),
Detection - CDV700?? or RadAlert 100?? or the upcoming Doug Coulter 2011 model??
HV - Already have 15Kv, 30ma NST (for the fusor route).

I have researched and understand most of the limitations of each device but so far I am totally "book learnd stupid" Anyone have an OMG, don't use that reaction or sage advice?

I laugh at myself and feel arrogant to even step into this arena with my knowledge level but thats never stopped me before.

Charles
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Re: Hi from North Carolina

Postby chrismb » Sun Feb 06, 2011 2:00 pm

csnyder wrote:This is probably too many entries on an intro but still introductory so...
It's your intro, Charles, go where you wish with it!!

Looking back in the archives of the Fusor Forum, there was a lot of enthusiam that seems to be missing or squelched now.
I think that sums up why Doug wanted to get this forum painted up as an apron for people to taxi their ideas into. I guess we're here because we share that view.

1) LDX fusion - I dislike overly complicated, job security type devices - IMO, the space shuttle, tokamaks and car engines :) - OK, no-one get upset with my list, I understand some things will always be complicated.
Not sure I am one to say much about LDX, but I would not look at something in terms of its apparent complexity. The fusor is beguiling in its apparent simplicity, but its operation is complex. I'll say, in an attempt to be sympathetic to the way you are looking at this, that a very complex device might be necessary to drive a simple, stable system, whereas a simple system may end up in vast complexity, so I think perhaps the point of view to be considered is; what is the overall complexity, both for device and operation.

2) My starter "glow" system -

Pump - Welch 1402 (quiet, cheap/easy to overhaul, good cfm)
Chamber - Quartz dome 15" (on EBAY for now, understand the risk of localized heating implosion, shielding requirements etc),
Detection - CDV700?? or RadAlert 100?? or the upcoming Doug Coulter 2011 model??
HV - Already have 15Kv, 30ma NST (for the fusor route).

I have researched and understand most of the limitations of each device but so far I am totally "book learnd stupid" Anyone have an OMG, don't use that reaction or sage advice?
I am sure we'll help work with you to iron out the details!

I laugh at myself and feel arrogant to even step into this arena with my knowledge level but thats never stopped me before.
Ditto. But I go by one view of the world, and one only; if someone else can understand a thing, then I can understand it. Ignorance is not a bar to progressing something for which one is inexperienced, it is merely a time-cost to get up to speed. Also needed is a thick-skin that you don't mind feeling like a bit of a novice outsider whilst you are with, and draw in, the experience of the old-timers. Those old-timers that don't like being asked the 'basic' questions aren't the ones thinking about the fundamental issues, they're the ones already set in their ways, and for whom the world will never change.

As I say; "You can tell the old-timers. But you can't tell 'em much!"

You can fix ignorance, easy, providing you're smart. If you can build your own 'plane, I think you've got no worries as long as you have the discipline to pick out the max climb-rate up the learning curve.
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Re: Hi from North Carolina

Postby Doug Coulter » Sun Feb 06, 2011 2:42 pm

Some old timers you can tell -- I ain't no spring chicken, and despite fast living, haven't died hard (yet). I think it's already past the point of leaving a good looking corpse. I'd guess Chris has some reason not to have put up a picture of himself as well (just kidding ;) ). If pixels and computers don't mix well for him, he can always send me a photo and get me to do it!

LDX actually looks extremely complex to me, and superconductors right next to fusion -- as they say on Slashdot, "GoodLuckWithThat". I'd love to play with all that, but live kinda too far from a source of affordable cyrogenics (which might be true for everyone with that "affordable" qualifier).

I have no objection to using magnetic fields for things in general. However, they only affect moving particles and then only to make them tend to spiral around the lines. Containment is pretty iffy, as 100% or so of existing attempts seem to show, very roughly speaking. Directing and guiding seem wiser uses of that particular force, but I am willing to be shown a better way. Static containment just doesn't seem to actually work for anybody with H fields. Plasma is pretty snaky stuff...hard to handle at all, much less with a force that only ever acts normal to particle motions. I suppose the hope there is, that while two wrongs don't make a right, two rights can make a U turn.

As Chris points out, what is actually going on inside a plain old fusor is both complex and very poorly characterized in actuality. We have searched the literature widely for people measuring things I think might be important (like which polarity particles are going which way where, and how many, little things like that) and come up mostly a totally blank slate. Of course, if you go to fusor.net and ask "what are the rays" you'll get a number of opinions that is roughly twice the number of posters! And all of that is "it has to be" or "it oughta be" -- still no measurements.
I've learned to take that kind of armchair theorizing by people who only half-grasp an oversimplified version of the theory with a grain of salt, at best (this makes me unpopular in some places).

So, I determined to start grad school here, if you consider fusor.net grade school. Here we don't accept things because someone said so quite as much, and here it's also ok to out-do the teacher in your research, and in fact, encouraged. A saying I often use in sigs is "Why guess, when you can know, measure it!".

It seems pretty obvious to me that nearly all the "theory" people come up with for fusors is in the class of "that's not even wrong", frankly. One example is recirculation -- why should that happen at all? I further tried to measure it and could detect none at all. I see the spring and the mass...that's a tuned circuit, not an oscillator. I measure a huge excess of electrons with a faraday probe that "armchair" theory says shouldn't be there, but it's there. And so on. Further, almost none of the fusor people (so far) have a clue about nearly a century of charged particle work in practical usage -- vacuum tubes. I think quite a lot of that can be valuable to us, but no one looks in the old books. After all, a proton acts pretty much like a heavier electron with the other sign of charge, as far as controlling them, making them flow and focus, all that. Here we have a more complex system -- both flavors of charge in a normal fusor, which allows for other things to creep in -- various emergent behavior, but that doesn't mean you first toss out existing knowledge before tackling the next step, at least, not to me. And in fact, I'm looking at approaches that simplify all this by getting rid of the electrons insofar as is possible. Well, that's my rant, yours is yours.

I would suspect that any dome that size you got affordable on E bay isn't quartz -- Ask MarkB what that would cost and the number of digits alone will amaze you. Probably 5 (used) or 6 (new) of those in base 10. You've probably got borosilicate, which is fine, actually. You will have to take measures to protect it, at least a metal screen with 100% coverage, or a metal box it sits over, otherwise it will break, and before that, it will be ruined by charged particle impacts and radiation. While being sputtered with metal from any charged electrodes in there. Even in my metal tank, I have to put a sacrificial glass piece inside the windows, and those pieces don't live many hours of operation before they become cracked and blackened. Just an FYI.

You'll get to glow with an NST, but nearly 100% of those are center-tapped with the center tap to ground, and it's real hard to change that. You can use one in a full wave CW multiplier to get the DC volts you need fairly well, especially if you resonate out the huge series inductance they have built in as a ballast, but that takes larger capacitor values than using a high frequency version. This won't help with the also huge series R they have built in of course. A 60 ma 15kv NST will only put out about 10 ma at 15kv (if you're lucky) -- the current is the short circuit current rating. Of course, if all you want is glow, AC is fine, and half of a big NST works very nicely -- it's what they were made for! The built in current limit is useful there while you learn.

You'll also get to glow with the nice Welch (I like those myself). But no one has gotten to really good fusion with just that. Sadly, most all fusors need to operate in a range a little better than any mech pump can get a real world chamber to, while a diffusion or turbo pump tends to be overkill and hard to control. You just can't get to pressure and purity requirements at the same time with just a mech pump in the presence of outgassing, one of those "sad but true" situations.

Everybody should have at least a plain old geiger counter (one with a thin window that can see alpha particles is good for other uses too). A real CD-V700 should do fine - It should be good enough to show you the cosmic ray background at a minimum, and most of those will (not the old super numb ion chambers though -- they only read awhile after you are dead). I strongly reccomend that it be hooked to some kind of audio output so you can hear it go, it's better and you can't ignore it or forget to check that way. Even my little survey meter has a little speaker and driver I added to it to hear the clicks, it's a super nice (and easy to add) feature. I used one transistor, a headphone speaker, and a 9v battery to make mine. This isn't so useful in detecting fusion, but it's kind of a mandatory safety device as when you have fusion, you're going to have X and gamma rays too, in general. In my system, almost as much energy goes to that as does to heat -- it's loud. We'd like to keep you around!

In short, avoid the really old ion chamber/dosimeter type Civil Defense stuff. I put one of those nice dosimeters in a box with, well, hot rocks (Nuclear waste) that my scint counter sees from 10 feet away -- right through the lead walls -- and in a month, it finally just began to read at all. There's enough rads in that box to kill algae and cockroaches! And the ion chamber/meter says the box is cold. Yeah, right -- it utterly saturates a decent geiger counter with the lid off from about 3 feet -- this is one I keep outdoors! There are some nice parts to scavenge in these (an electrometer tube and some real high value resistors) but otherwise, it's a nice box to build something else into.

I'm using electron cyclotron resonance acceleration in a microwave ion source I use here. I know at least Chris and I both think mere thermal energy cannot be the way to go, and got started discussing a paper that shows why on another thread here. Basically it amounts to this -- thermalization means all the energy is split up into all the degrees of freedom, which is at least 3 for a proton (XYZ) and 6 for anything you can notice rotation on around those three axes. So 5/6 of the input energy is wasted, more or less. Further, it appears nearly all the losses are from various ways electron energy gets changed into photons, so if you had a choice (and I think you do) you'd just as soon not have them at all.
Posting as just me, not as the forum owner. Everything I say is "in my opinion" and YMMV -- which should go for everyone without saying.
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