It had been awhile since I looked around for serious polywell news and my searches this week yielded some interesting results that may have eluded people's notice here. Was this a moment in time when I was ignoring SN or the "Other Site"? I can't find evidence of that just now. On to the scoop:
EMC2 submitted a preprint to arXiv with some results around confinement this summer. Did anyone notice?
After getting extended funding two years ago, the folks at Energy Mass Conversion Corporation have continued their work, and this last summer submitted their preprint — not immediately impressive since they focus on proving aspects of the WhiffleBall, and not on producing fusions per sé. The resulting discussion at talk-polywell ended shortly thereafter and currently runs to 137 posts. The first few dozen were more light than heat — and not very much of that beyond the understandable sparklers of celebration that something was emerging. They eventually get more content rich and I haven't plumbed everything that's said — nor indeed the paper itself.
More interesting to me were the comments on this news story, especially those by the chap who says "'not implausible' is not the same as plausible". Also of interest is a stack of slides appealing to politicians (US politicians — not much good to me in the True North) for funding (remember Dr. Bussard's "rice bowls"?), part of a larger collection that is linked to from the last one in that stack.
[Update]
For those who may not already be familiar, Wikipedia explains:
The polywell is a type of nuclear fusion reactor that uses an electric field to heat ions to fusion conditions. It is closely related to the magnetic mirror, the fusor, the biconic cusp and the high beta fusion reactor. A set of electromagnets generates a magnetic field which traps electrons. This creates a negative voltage, which attracts positive ions. As the ions accelerate towards the negative center, their kinetic energy rises. If the ions collide in the center, they can fuse.
The polywell is one of many devices that use an electric field to heat ions to fusion conditions.[1] This branch of fusion research is known as inertial electrostatic confinement. The polywell was developed by Robert Bussard, as an improvement over the fusor. His company, EMC2, Inc., developed the initial devices for the U.S. Navy.
(Score: 2, Informative) by tadas on Saturday October 11 2014, @12:01PM
Could someone please explain, in English, what this article is about? When you submit an article, at a minimum, a reader unfamiliar with the field should at least be able to tell *what* field it is without having to click the links or resort to Google. Is this programming, hardware hacking, global warming, internet security, Arduino, electric cars, or Santa Claus?
I clicked on one of the links and found this:
We report experimental results validating the concept that plasma confinement is enhanced in a magnetic cusp configuration when beta (plasma pressure/magnetic field pressure) is order of unity.
Wow, really helpful!
Stumbling around further, I found that this has something to do with nuclear physics. Would it have hurt to mention that in the submission, together with why we should care?
(Score: 0) by Anonymous Coward on Saturday October 11 2014, @12:20PM
I was pretty confused, too. I think it made more sense after I read about field equations [wikipedia.org], the interacting boson model [wikipedia.org], proton-proton chain reactions [wikipedia.org], and intertial electrostatic confinement [wikipedia.org]. I still don't fully understand it, but at least I'm not completely lost like I was earlier.
(Score: 2) by mtrycz on Saturday October 11 2014, @02:00PM
Is it bad that I found this funny?
In capitalist America, ads view YOU!
(Score: 0) by Anonymous Coward on Saturday October 11 2014, @02:51PM
Dear Lord, no. That comment captures the essence of what made Slashdot great, back in the day.
(Score: 2) by romlok on Saturday October 11 2014, @12:30PM
To me, just about the entire submission read like it was written by one of those random science-paper generators.
(Score: 2, Informative) by Jesus_666 on Saturday October 11 2014, @02:24PM
"WhiffleBall" (or "Wiffle-ball") is a specific model of inertially confining plasma. It's more efficient than other models but has, only been proven to exist in the paper TFS talks about. The details are only relevant if you're really interested in the specifics of polywells but the fact that this hasn't been proved in the 80s is one of the reasons why almost everyone is working on tokamaks these days.
Polywells could become very interesting as they lack a few downsides tokamaks have (and of course have a few of their own), but for now they're in a very early stadium. Still interesting if you're into fusion power.
(Score: 2) by Immerman on Saturday October 11 2014, @05:21PM
Almost - I am also not an expert, but have been following the Polywell for a while and think I can clarify a few details
First the background for those unaware:
At the level of individual atoms temperature and velocity are interchangeable, and the ion "heating" is achieved by the ions "falling" into the extremely deep well of electrostatic potential. The original design, the Farnsworth Fusor , uses two concentric spherical electrodes to generate a spherical electrostatic field of tens to hundreds of thousands of volts, which causes ions to fall towards the center. The central electrode is typically a sparse wire mesh which allows the vast majority to ions to fall through it to collide in a point in the center. A small fraction will fuse during the impact, and the rest will miss or bounce off each other and race back up the potential well, almost escaping before falling back to the center with negligible energy loss. Each ion may make that journey thousands of times before fusing, but since there's negligible energy loss you only have to supply the energy for the first pass, everything else comes for free as the ions "orbit" the central point on a highly elliptical (and energy conserving) path.
And as it happens this is actually an extremely cheap and effective way to generate fusion - anyone with a few hundred bucks worth of equipment can build a working fusion reactor in an afternoon if they just want an energetic neutron source. (translation: don't build one unless you know what you're doing and WANT to be bombarded with neutron radiation) The difficulty is in achieving break-even power output. The problem is that central wire mesh electrode - very few ions hit it on each pass, but with each ion averaging thousands of passes before fusing those odds add up, and whenever an ion hits the mesh its kinetic energy is lost. Lots of work was done with different electrode designs, but losses were never reduced quite enough to achieve break-even power output.
And that's where the Polywell comes in. The polywell replaces the inner mesh with a "virtual cathode" made of magnetically confined electrons. With nothing to hit the ions are then free to recirculate indefinitely, providing a 100% conversion of electrostatic power to fusion events. Or at least that's the ambition. Actually confining the electrons densely enough to generate the required electrostatic field is challenging, and over time electron-ion interactions still leach kinetic energy away from the ions that gets shed as Bremsstrahlung radiation, so there's still a race against time in getting the ions to fuse before they lose too much energy, which typically means increasing the potential field so that ions collide at higher energies and are more likely to fuse.
And as I recall on that front at least the Polywell seems to have proven itself, as it's achieving orders of magnitude more fusion events at a given voltage than more traditional fusors. It remains to be seen whether they can retain that advantage when scaling to fusion densities high enough to generate net power output.
Just as an aside, as I understand it Dr. Bussard's original ambition didn't call for a magnetically confined virtual cathode - instead the plan was to continue to use the sparse wire cathode, but enclose it in a magnetic field designed to deflect ions from colliding with it: no collisions = no creeping energy loss, and break-even could be achieved. Presumably either I misunderstood the early descriptions, constructing such a field proved impractical, or the virtual cathode idea caught his attention as even more promising. Can anyone offer further insight on that?
(Score: -1, Redundant) by Anonymous Coward on Saturday October 11 2014, @12:02PM
It would be helpful if the summary told us what exactly a "polywell" is. Not all of us have the time or inclination to look up stuff like that on our own.
(Score: 2) by mmcmonster on Saturday October 11 2014, @12:21PM
Based on the article title, I thought Polywell was the name of the author.
(Score: 0) by Anonymous Coward on Saturday October 11 2014, @12:22PM
Ok that makes sense. So Dr. Polywell submitted some academic article. I wish the summary would have made that clearer! It makes sense now thanks.
(Score: 1) by tadas on Saturday October 11 2014, @12:33PM
Based on the article title, I thought Polywell was the name of the author.
That doesn't jibe with submitter's reference to looking around for "serious polywell news", and a reference to a "talk-polywell" site.
(Score: 0) by Anonymous Coward on Saturday October 11 2014, @12:40PM
Dr. Polywell is so important and famous that some people follow just the Dr. Polywell news, and even have mailing lists where they talk about just his work.
It's like how some people follow political news closely, and then chat politics online. But in this case it's people talking about Dr. Polywell and his work.
(Score: 1) by EETech1 on Saturday October 11 2014, @12:47PM
I thought a PAYWALL at arXiv?
That sucks...
PolyWTF???
(Score: 2, Interesting) by khallow on Saturday October 11 2014, @12:36PM
The current work is funded by the US Navy and started with research from Robert Bussard et al.
I don't know if participants in the polywell research still discuss their research on the above thread, but they used to.
The current work mentioned above is discussed in this thread [nasaspaceflight.com]. I haven't read through either the paper or this thread, so I don't have anything to add on the subject.
PS, I was reminded of this SN article [soylentnews.org] among other things, asking for ways in which SN could get mentioned. Well, here's one way. To corner the market, so to speak, on some esoteric subject so that people are likely to refer to you whenever they think of the subject in question.
(Score: -1, Offtopic) by Anonymous Coward on Saturday October 11 2014, @12:45PM
Linux and open source software was the "esoteric subject" that /. cornered for some time. I don't think that this overly scientific stuff is a good area, though. There are probably only about 6 or 7 people in the entire world who can understand this stuff. The rest of us Perlers and Linuxers find it interesting, but we don't really understand it. And there are a lot of us Perlers and Linuxers and MySQLers and Apacheers! LAMP stack, baby, that's where it's at.
(Score: 1) by khallow on Saturday October 11 2014, @01:05PM
(Score: 2) by aristarchus on Saturday October 11 2014, @07:23PM
I don't think that this overly scientific stuff is a good area, though.
But why would you not think this? It seems to be that "overly scientific stuff" is to "no one told me there would be math!"
(Score: 2, Informative) by Anonymous Coward on Saturday October 11 2014, @12:38PM
Not the approach I would have taken. Mine is:
1) Design and Make oversize, waay overunity core. Aim directly at p-B11, for pulse mode. If it burns itself out, because too much fusion? WIN!
Build the high tension power converters into the support structures: Use two unlinked high Q tank circuits, one between the coils and a big ultracap bank, the other between the magrid and high voltage energy storage coils placed within the support struts. Ring them up between "shots" whilst the turbopumps get close to the right vacuum.
The magrid-container to ground cage and electron emittor arrangement forms a capacitor backed up by strings of caps within the support struts, as well as the voltage drive for the electron emitters - guns not needed, just DC charged grids to keep the electrons from getting in before it's time to fire. The spherical electron field about the magrid during operation will suck back in any electrons that leak out the cusps in operation without sufficient speed to get away past the ground screen cage.
The magrid coils meanwhile connect to their (low volt, high current) caps forming the inductor half of the other resonant circuit. Both circuits have separate kicker supplies to pulse power in for part of every resonance oscillation, as appropriate.
2) Ring 'em up to firing energy, and the cycle or two before they're just about to beat both aligned, fire off the magnetrons to induce neutral ionisation within the magrid whilst there's a magnetic field but whilst the voltage is out of phase (two uncoupled resonant tank circuits at different frequencies will beat). This will create a hot low pressure plasma in the relatively strong magnetic field without electron injection, which will rapidly piss itself out of the cusps, thus clearing most of the remaining neutrals out of the way, for a little while at least. (some will want bounce off the walls, neutralize, then bounce back in, so this needs careful timing.)
At the right moment, fire off a tiny heated isentropic nozzle with a teensy quantity of hot hydroborane gas. The nozzle will cool the gas as it expands, and if aimed properly, the pulse of gas will form a small, expanding cloud too small to bridge completely a magrid - so it, left to it's own trajectory, would pass straight through the whole magrid before hitting things.
Coincide this to reach just inside the magrid just as the electrons are released by gating the grids over the primary electron emitters. The sudden drop in impedance of the voltage resonance as the electrons pulse in will dampen it, and discharge the caps, but this pulse only needs to last long enough for fusion to complete on the fuel. Ditto for the magnetic field, although the wiffle ball pushing back should actually tend to charge it up, as some of the energy couples back into the magrid's field from the electrons.
Huge pulse of emitted alpha from the fuel going off will flash across the magrid-ground screen gap, partially charging it back up again, and more than likely ablating it - this thing won't have a long service life.
A second power grid, outside the ground screen, will allow high tension output voltage conversion of the alpha's, if it's maintained around 1 MV or so, it'll even do so relatively efficiently.
3) A coupled, cylindrical configuration of wimhurst-like electrostatic machines, still within the high-vacuum chamber, will allow a constant-current DC conversion from the ~MV output voltage back down to a higher current at the ~200 kV level, such as is necessary to kick the resonant main voltage drive tank. This here is the "closed loop" part of the whole thing, without which it won't self-sustain. (No "chain reaction" here people. Those alpha's are too fast and the wiffle ball far to thin to lose much energy anywhere within the magrid.)
The cycle repeats with fusion happening in very low duty cycle pulses - with each alpha pulse replenishing charge on the high tension output. If it makes break even, then rebuild/fine tune it enough to run for a few days to weeks preferably.
4) Then strap on large fans and hover the whole thing somewhere public, so that after a few days of untouched, unrefueled operation, it's very clear that it cannot be just a hoax.
This last step is sadly totally necessary.
The Wright brothers didn't just keep trying until they merely succeeded at flight. They had to spend their careers flying in front of crowds until enough people had actually seen them fly with their own eyes before the general public took them seriously, and stopped listening to the "experts". There are enough "experts" at fusion already for this step to not be required.
Simply proving it works in a lab isn't enough - it really would take an extraordinary proof - doing some stunt that is otherwise impossible, publically where onlookers can see with their own eyes - before those guys who say the thing will never work - IE (isn't plausible) will have lost enough credibility to be ignored by the money.
Those guys are certainly about - they're the plasma physicists who "groan" about the physics of the thing, because they "know" it won't work. Well here's the thing: That "plama beta" ? Wrong number, only the electron beta part counts for shit. And secondly, the debye screening length? Orders of magnitude longer than the entire reactor dimensions. So fuck off and go back to you elementary fusion physics textbooks. Arsehats. This is indeed an identical situation to what the write brothers faced, with "Flying machine experts" who "knew" that heavier than air flying machines would never take off - and kept saying so - and being taken seriously! - literally decades after the first fully-controlled powered human heavier-than-air flights. (guy's name was Otto, he gave up on the general public, and started a company to make - guess what - airplane engines...)
After that - these things will probably be closer to gas turbines than base load power stations - great power to weight ratio, great peak power, but not so long service lifes or efficiency as other approaches. (eg, LFTR. There is more energy in Thorium everywhere, than there is in Boron-11).
So, figure single-stage to orbit becoming something that can take off at international airports, and which drop the cost to orbit by 1000-fold.
Bigger versions built in orbit might use pulse mode purely for startup, and thereafter run steady-state - the vacuum is easy after all - and less worry about neutrals bouncing back if there are no vacuum chamber walls. Such engines would make efficient interplanetary cruise ships. Earth-Mars in a couple weeks... Earth-Saturn in a couple months.
Hello near infinite virgin resources, but you'll have to become more personally and intimately familiar with this universal problem life has called "survival".
You're probably mostly unaccustomed to having to worry about it, being that our immediate environment generally doesn't kill us right away, but most of the universe is a bit harsher than that.
We'll have little choice but to collaborate on that - and national divides make a whole lot less sense to fight about up there, when we're all from the same little dot anyway.
Peace out!
(Score: 0) by Anonymous Coward on Saturday October 11 2014, @12:42PM
I was going to ask you for citations, but then I realized that your comment is so thorough and complete that it can in fact be used to cite itself.
(Score: 1, Redundant) by mtrycz on Saturday October 11 2014, @01:56PM
To the submitter: Please, don't assume people already know what you're talking about. Was it really so hard to add:
"[...] polywell, a type of nuclear fusion reactor, [...]" with a link to wikipedia?
To the editor: unless you're already familiar what this polywell is (doubt it), you've checked it on wikipedia to see if TFS was legit. Was it so hard to add: "[...] polywell, a type of nuclear fusion reactor, [...]" with a link to wikipedia?
When you read major recognized media, they feel the need to clarify who Edward Fucking Snowden, the NSA whistleblower, is, putting you in context, introducing you to the article. I think it's a good standard and something we could use more of.
I already know how hard it is to write/edit a high quality summary, and I'm not trying to bash on you, because I appreciate your work. Just wanted to point out that putting some context into the summary is a good rule of thumb.
In capitalist America, ads view YOU!
(Score: 3, Interesting) by ansak on Saturday October 11 2014, @03:02PM
To everyone else: "Was it really so hard to add...?" No it wouldn't have been. I just didn't think to do it. My bad. I'm always on the watch for black swans in the energy field without going too crazy on clear [wikipedia.org] scams [wikipedia.org] and I thought more than a few other folks around here would be, too. I thought it a reasonable assumption but even if it was, I took it too far.
Polywell Fusion hit a chord when I watched the original "Should Google Go Nuclear" [youtube.com] within a month of it coming out. Probably that would have been because I recognized the guy's name from a "ramscoop" [wikipedia.org] engine mentioned in some Science Fiction I really enjoyed in high school in the 70s -- and I've been following it like a supporter of "Dagenham and Redbridge" [wikipedia.org] would do even if he relocated to some village between Kunming [google.com] and the Laotian border (any way he can) ever since. Of course nobody else is that many sigmas [wikipedia.org] off normal and I should have known better. Mea culpa. Mea summa culpa.
As for soylent news becoming popular for glomming onto edge subjects, that wasn't what I intended. In this case it isn't even necessary: talk-polywell [talk-polywell.org] is filling that bill for the real discussions adequately, along with enough ignorant hooting (what do you expect from fans and True Believers?) to make it hard for someone like me (or I expect many of you) to find the important bits. This week I noticed some important bits, so I flung them up at the wall to see if they'd stick, to let other swan watchers know that the dial had ticked forward a notch or two since last time more than a few people were looking (probably when the US Navy started funding EMC2 again). Why? Mostly because I'm convinced that the discussion of energy futures tends to be WAY too narrow, that combusting hydrocarbons (especially really long ones and cyclics) is a crime against the future along with other depletions and any variety of long-term toxification, too numerous to itemize here (don't get me started) but including chemical plumes in ground water and long term post-fission waste. Our vision just isn't big enough yet.
On the fusion front, the tokamak gets almost all the oxygen which makes as much sense as people being so focused on DC electricity that AC never gets developed into something that can serve the populace on a massive scale -- fortunately, that ended well back in those days -- and is likely being reversed as the grids' needs are changing. Intellectual nimbleness is always a good thing. (all of that is searchable on Wikipedia, folks: fill yer boots)
To me the best fix for that does not include hand-wringing and moaning. What it does include is watching and waiting for the swans, and if we can find any potential candidates (real ones, not Perpetual Motion Machines and Hyper-efficient Carburetors), to talk them up a bit in the general populace:
Maybe our words will leak out to the ears of someone (probably someone younger: at 30 most of us are pretty set in one career or another with little chance of successful massive reinvention) who is more capable of pursuing them to a successful result than we.
Maybe it'll reach the ears of someone with a few billion dollars in their pocket wondering what outliers to fund.
Maybe it'll reach the ears of some lawmakers -- I can think of much more wasteful places to put more of my tax dollars than polywell or laser-ignited [wikipedia.org] or magnetized target [wikipedia.org] fusion (not to mention solar-cell breeders [ssb-foundation.com] if anything should come of that: still watching). And if they heard it and did something about it, it only increases the chance that the result (at least the 2nd and 3rd order results) could be of great benefit to all of our six or seven billion human neighbours, never mind our non-human neighbours and this lovely ball [cockburnproject.net] we live on.
And that'd be a good thing.
(Score: 1) by khallow on Saturday October 11 2014, @07:43PM
On the fusion front, the tokamak gets almost all the oxygen which makes as much sense as people being so focused on DC electricity that AC never gets developed into something that can serve the populace on a massive scale
It's also probably why there's so little thorium reactor research in the developed world too.
(Score: 1) by ansak on Saturday October 11 2014, @08:32PM
Not quite but related. The advent of Thorium research would have been about 75 years ago, competing for dollars with fuel cycles that could be used for weapons and civil uses. The situation (other project sucks up all the money) would be the same but the cause of the situation for Thorium (can we make a bomb, too?) doesn't apply in the least to tokamak vs. other fusion ideas.
Doesn't matter how you lose your oxygen, though. It still means you can't breathe. ...ank
still looking for Gentle Treatment
(Score: 2) by PinkyGigglebrain on Saturday October 11 2014, @03:58PM
I would like to add that they should drop the whole "First time submitter ..." shit.
Who the fsck cares?
It was one of the things that ticked me off about slashdot.
"Beware those who would deny you Knowledge, For in their hearts they dream themselves your Master."
(Score: 0) by Anonymous Coward on Saturday October 11 2014, @02:32PM
It has been shown that it is NOT possible to design a fusor type device that does not leak. They will ALL leak. You can put the wires closer, but they will still leak plasma because the electric field leaks and plasma will flow out along the electric lines. This is why fusor devices were abandoned very early on. It is quite unlikely that they will ever work to produce net energy.
On the other hand, a tokamak design does not leak. It's 100% sealed. It's just a question how you touch the plasma and make it flow in the confinement which has been worked out despite serious challenges not imagined before work started. Actually, computer simulation is what enabled ITER to be designed - something that would not have been possible 30 years ago.
Anyway, good luck to the polywell people. Really. But it's more of a "pie in the sky" ideas when it comes to fusion devices for power production.
(Score: 1) by khallow on Saturday October 11 2014, @07:52PM
It has been shown that it is NOT possible to design a fusor type device that does not leak.
And why is that considered a problem significant enough to rule out the design? I understand a bigger obstacle is leakage of energy from the plasma to the wires themselves. That apparently is the problem that the polywell design attempts to reduce.
(Score: 0) by Anonymous Coward on Saturday October 11 2014, @09:08PM
It seems that what they're allegedly proving in this paper is that once you get past a certain threshold in the confining field strength, the confinement goes way up. I am not sure how this makes sense.
(Score: 1) by ansak on Sunday October 12 2014, @04:58AM
For my part, the fact that grandparent mentions "wires", suggests that this poster has not examined the difference between a Farnsworth-Hirsch fusor [wikipedia.org] which uses nothing but electrostatic containment and suffers from leakages as the poster asserts will always be the case, and the Polywell [wikipedia.org] variety which (experts: correct me if I've got something wrong in this one-clause synopsis) exerts magnetic pressure on the plasma that was built up by electrostatic means and by that means, according to the referenced arxiv paper, can seal off the leakage entirely. Not a final "yes" but an exciting step from what I can understand.
Complicated stuff all of it, and not made any clearer by my unclear title etc. etc.
cheers...ank
still looking for Gentle Treatment
(Score: 0) by Anonymous Coward on Sunday October 12 2014, @04:58PM
And the magnetic field design there also leaks.
However you cut it, the geometry of the device leaks. That's why toroidal magnetic field were initially looked at with such incredulity - it does not leak.
What does this mean? It means the polywell will most likely achieve fusion. But it will not really be usable for actual net energy production. It is easy to get fusion working. It is not so easy to make it make energy for you. In their paper, they have a nice photo that nicely shows the same plasma leaks as with the old fusor.
EMC2 is planning a three-year, $30 million commercial research program to prove the Polywell can work as a nuclear fusion power generator
Good luck to them. If they can make it work, that would be wonderful news. Most likely result will be nowhere near net energy producing. But maybe they can show something interesting in plasma physics field. We'll see, hopefully.