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Dr. Bussard Passes Away, Polywell Fusion Continues

ScuttleMonkey posted more than 6 years ago | from the fighting-the-fight dept.

Power 79

Vinz writes "Dr Bussard, the man behind the Bussard Collector and inventor of the Polywell fusion device, passed away last Sunday in the morning. He leaves behind him a legacy of EM fusion devices, and a team determined to continue his efforts. The news of funding extension for the construction of his WB-7 fusion devices made it to slashdot months ago (as well as his talk at google). They may be a serious candidate in the run to bring commercial fusion, and may work at lower scales than other projects. Let's hope the project continues in good shape despite his departure."

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79 comments

Aw, man... (1)

Tetsujin (103070) | more than 6 years ago | (#20959369)

With no Bussard, where are starships going to get their blinky engine lights from?

Re:Aw, man... (1)

Applekid (993327) | more than 6 years ago | (#20959539)

We've got our switches, lights, and knobs to deal with, Striker. I mean, down here there are literally hundreds and thousands of blinking, beeping, and flashing lights, blinking, beeping and flashing - they're flashing and they're beeping. I can't stand it anymore! They're blinking and beeping and flashing! Why doesen't somebody pull the plug?!

Re:Aw, man... (1)

edittard (805475) | more than 6 years ago | (#20961107)

Are they flashing out of sequence?

Passes away? He DIED! d-i-e-d-!! (0)

Anonymous Coward | more than 6 years ago | (#20961543)

Passes away? He DIED! d-i-e-d-!!

Re:Aw, man... (5, Insightful)

rickola (1172965) | more than 6 years ago | (#20960019)

I posted the following to the TrekBBS: "Dr. Robert W. Bussard has died. Star Trek tech fans will know the name, though perhaps not the man himself, from the matter scooping mechanism he proposed and which we finally named in his honor on The Next Generation's U.S.S. Enterprise. By all means check Google and Wikipedia for further information about his accomplishments and hopes for new energy and propulsion systems. I knew him for a time in the early 1980s, as I had written an article on interstellar travel for Science Digest magazine that included his concepts as well as those of Drs. Robert Forward and Robert Enzmann (the three "Bobs" of far future flight). As part of the scientific help Bob Bussard gave me for that article, he sat in my living room in Irvine, California, scribbling calculations for waste heat radiators on a new version of his ramjet ship, and it was a wonder to watch and listen. It was an honor to translate his doodles and numbers into finished art. He was generous with his time and knowledge, and while I hadn't talked to him for a few years, I will miss him." It seemed fairly obvious that folks like "Franz Joseph" Schnaubelt, who drew up the deck plans for the original series U.S.S. Enterprise, knew something of Bussard's ideas for the ramscoop, since the spinny red caps were labeled as "matter/energy sinks" or something very close to that (my copy of the plans is away in a box). I'm not certain that Matt Jefferies heard about the scoop at the time he sketched the ship out, but he might have. When it came time to do Star Trek: The Next Generation, we in the techy side of the art department decided to give a name to the hardware, and so it shall stick. Rick Sternbach

Re:Aw, man... (0)

Anonymous Coward | more than 6 years ago | (#20960713)

Fiction with mentions of his works, particularly the Bussard collector/ramjet, inspired many of us to dream of the stars. Adding the race to the moon with NASA leading the charge and hiring many and paying for much research fueled the dreams more. Such dreams decided the futures of many. When TOS was cancelled, SF began to give way to fantasy, nuclear energy got black eyes while being cast aside, NASA begin to fade and many of the carreers were forced onto to sideroads, the dreams died for some, planned careers were forced to change and many of us were sad.

Many of the great SF writers have passed away in recent years, before and along with them have gone many of the scientists that inspired them and were inspired by them as well as each other, only the dreams and their followers remain. It is a shame that the Bussard ramjet was decided to be most likely ineffective in use due to the relative lack of free hydrogen in space. It is also a shame that his fusion device work didn't come into fruition within his lifetime. Many of us have had to, with age, wisdom and disillusionment pouring in, come to the conclusion that our dreams will not come to fruition within our lifetimes.

This death notice brought tears to my eyes because it is not just the death of a man, not just the death of a successful scientist, it is a reminder that dreams don't always reach fruition while one is alive regardless of your hard work. There is no doubt that if mankind is to survive we must find new energy attainment methods and must reach the stars. We must continue to dream and pass the dreams along while inspiring new ones along the way to the stars.

Larry Niven & the Bussard Ramjet (1)

Thomasje (709120) | more than 6 years ago | (#20961293)

I thought Larry Niven named the matter scoop after Bussard -- in his Known Space novels and stories, there are frequent references to "Bussard Ramjets", a fictional propulsion system consisting of an electromagnetic scoop that collects hydrogen from space, and a fusion-powered rocket that uses some of the hydrogen for nuclear fusion, and uses the remainder as reaction mass. I'm pretty sure this was long before STtNG.

Re:Larry Niven & the Bussard Ramjet (1)

rickola (1172965) | more than 6 years ago | (#20961621)

Oh, I didn't mean to say that we were the first to name a piece of space hardware after Bussard, just that we did it specifically on Star Trek for a bit of the machinery that fit. I also learned about the ramscoop/ramjet by reading Larry Niven's books - as well as illustrating them. :) Rick

ideas are cheap (1)

m2943 (1140797) | more than 6 years ago | (#20962703)

This is not to diminish his other work and Bussard may have accomplished other good engineering work, but if anybody should get credit for the "Bussard collector", it should be the people making it actually work eventually. If it ever does work, the amount of brilliance that needs to go into the engineering (not to mention getting the funding!) will be far greater than the initial idea, an idea probably many people would have come up with by then independently.

His work on the Polywell is different: there he sat down to do get the funding and do the engineering and implementation himself. That's the really tough work. Unfortunately, after 12 years, results are still inconclusive, which raises the question whether the concept itself may be flawed.

Drag: Ramjet as parachute; RIP; Re:Aw, man... (0)

Anonymous Coward | more than 6 years ago | (#20967539)

When I worked on NASA contract for Dr. Dana Andrews at Boeing's Kent Space Center, in the slot later filled by Dr. Robert Zubrin, we were tasked with studying all known forms of fission and fusion and more exotic space propulsion. My friend Dr. Robert Forward worked the equivalent contract for USAF.

Hence we looked long and hard at the Bussard Ramjet. At this time the word on the street was that drag killed the Bussard Ramjet. That the Bussard Ramjet was actually an elaborate interstellar parachute.

I was responsible for several chapters of our report to NASA, including the one on Fusion propulsion.

In re-thinking Bussard's design, I looked at large superconducting rings carrying large currents, and how they would interact with planetary, solar, and galactic magnetic fields.

This included study of the earlier "ringsat" by James B. Stephens at JPL, a prolific inventor (in fact, #2 of all time at JPL) who pased away last year.

One issue was, could plasma pouring through the ring generate electric power to run ion propulsion?

The modeling got sticky. After I left and was quickly replaced by Dr. Robert Zubrin, our qualitative early model was replaced by the correct plasma physics equations, and Andrews & Zubrin are credited with inventing the Magnetic Sail.

My sometimes work with Dr. Robert Forward (see for instance the piece on slower-than-light edited by Dr. Geoffrey Landis on an interview with me, Forward, and Dave Brin) ended with Bob Forwards death from brain cancer.

I have since worked with Bob Zubrin (coauthoring his first novel and screenplay, but taking a cash bonus for removing my name from ther title pages).

I have know Larry Niven for a very long time, and adore his use of Bussard's star drive in science fiction.

One coincidence: Larry Niven, Dana Andrews, Dave Brin, and I all were students at Caltech, which administered JPL where Jim Stephens worked.

Hence all of this involves super-smart hard-working quirky people on the fuzzy boundary between science and science fiction.

When the sun expands and vaporizes the biosphere, Robert Bussard's atoms will flow out into the interstellar medium, where his mind had long ranged free.

-- Prof. Jonathan Vos Post

Re:Aw, man... (1)

danwat1234 (942579) | more than 6 years ago | (#20962375)

sheeeeep .... sheeeeep shp .... shp How much air does that door need to open/close?

Re:Aw, man... (1)

danwat1234 (942579) | more than 6 years ago | (#20962405)

Murdock: "What have you found?" randomguy: "All I've found is that these red lights keep moving back and forth. Aside from that this thing seems to have no other function! whatsoever sir. Murdock: "Well that's impossible, I mean.. it must have... some.. sort.. of function I mean why would they go and put all that money to a thing with red lights that keep going back and forth! It doesn't ...make... any sense. Keep working on it.

Final arrangements for his body. (3, Funny)

king-manic (409855) | more than 6 years ago | (#20959373)

I hope they cremate him in a fusion reactor. I'm sure it's hot enough.

Re:Final arrangements for his body. (5, Funny)

Tetsujin (103070) | more than 6 years ago | (#20960053)

I hope they cremate him in a fusion reactor. I'm sure it's hot enough.
Of course it is. Everybody knows there's no such thing as cold fusion...

Re:Final arrangements for his body. (1)

6Yankee (597075) | more than 6 years ago | (#20961681)

Either that or leave him out in the back yard as a Buzzard Collector.

Re:Final arrangements for his body. (1)

Rhinobird (151521) | more than 6 years ago | (#20963257)

*rolls up newspaper*

No! *smack* Bad 6Yankee, bad! No pun for you!

Mod parent up (0)

Anonymous Coward | more than 6 years ago | (#20967569)

I lol'd. An internet to you, good sir.

Re:Final arrangements for his body. (0)

Anonymous Coward | more than 6 years ago | (#20979169)

How come no one has modded this +1 funny?
WTF is the matter with you people?

I remember Star Trek. (0)

Anonymous Coward | more than 6 years ago | (#20963907)

I remember when they would talk about Bussard collectors that would collect hydrogen for fuel for their fusion reactors. I never made the connection then but now I do. Amazing! I really hope fusion comes into play this century. Fission is so messy and dangerous. I think my kids kids kids will have them as regular appliances in their homes. Man, can you imagine the energy savings!?!

Read the Wiki Article (2, Informative)

NeverVotedBush (1041088) | more than 6 years ago | (#20959579)

It's referenced in the summary. I hadn't heard about Bussard or the polywell. It sounds promising. Navy-funded research too. I'm sorry this person died before he could see it through to demonstration. Hopefully this really works.

Re:Read the Wiki Article (2, Interesting)

julesh (229690) | more than 6 years ago | (#20963757)

You should watch the presentation he made at a google tech talk last year. He was very enthusiastic about his work, and managed to carry that through to his talk, despite his obviously-poor health at the time. It was a great talk.

Re:Read the Wiki Article (0)

Anonymous Coward | more than 6 years ago | (#20964651)

I literally just watched that yesterday afternoon, so seeing news of his death was quite a shock to me.

If we are to believe what he says, the lack of funding for his project is an absolute crime: a tiny $200M dollars are all that are required to give a decent test of his theories (and if found true, the consequences are *truly* profound), and he was unable to secure it.

What a waste :(

A remark captured my attention (2, Insightful)

Anonymous Coward | more than 6 years ago | (#20959709)

According to Bussard, "The funds were clearly needed for the more important War in Iraq." [7]

http://en.wikipedia.org/wiki/Polywell [wikipedia.org] Ouch. In terms of value for money, though, gambling our money away on a wild scientific flier would be a much better investment than starting the war in Iraq.

The other thing that caught my attention was Bussard's comment that they should go straight to full scale. He may or may not be right. Most people who have been around the block more than once would be sceptical though. When you are trying something new, there is almost always a gotcha or two.

Re:A remark captured my attention (1)

wanderingknight (1103573) | more than 6 years ago | (#20959949)

According to Bussard, "The funds were clearly needed for the more important War in Iraq." [7]
Perhaps he was just being ironic?

Re:A remark captured my attention (1)

NeverVotedBush (1041088) | more than 6 years ago | (#20961339)

Or sarcastic?

Re:A remark captured my attention (4, Interesting)

nutshell42 (557890) | more than 6 years ago | (#20960715)

The other thing that caught my attention was Bussard's comment that they should go straight to full scale. He may or may not be right. Most people who have been around the block more than once would be sceptical though. When you are trying something new, there is almost always a gotcha or two.

It's one of the things that had the alarm bells ringing about the Polywell because it's something you'd expect from someone who wants to sell you the Brooklyn Bridge.

But I think in his case he just saw the writing on the wall. He knew he wouldn't see a full-scale reactor if it was done step-by-step, he was just too old for that.

I really hope someone with the required expertise will take an honest look at the Polywell. The concept sounds good and the central question seems to be whether the plasma will move into thermal equilibrium or not. And the paper every critic cites is one master thesis written by the student of one of Bussard's rivals for Navy funding. Hmmmm...

Now, the fact that your opponent's not trustworthy doesn't mean that you are, but I think that considering all the money that goes into ITER a few million for looking at different approaches (mostly this and lasers/inertial confinement =) are a good investment.

Re:A remark captured my attention (1)

seven of five (578993) | more than 6 years ago | (#20960907)

The other thing that caught my attention was Bussard's comment that they should go straight to full scale.

My understanding is, the current work is not for a full scale reactor, it's for WB-7, a more robust version of WB-6. The intention is to validate the concept with more results and longer runnings times. If and when WB-7 has produced some solid results, the results will be reviewed and deliberated. If the results merit further work, I believe the Navy will proceed with a full-scale model for net power.

I am sad for the loss of Dr Bussard and very happy that he lived long enough to see the project resuscitated. This is very exciting stuff. It has the potential to drive the last nail in the coffin of a filthy fossil fuel economy.

Makes perfect sense to me. (4, Interesting)

Ungrounded Lightning (62228) | more than 6 years ago | (#20961639)

The other thing that caught my attention was Bussard's comment that they should go straight to full scale. ... Most people ... would be sceptical... When you are trying something new, there is almost always a gotcha or two.

In this case he believed he had the scaling laws down. With power proportional to the seventh power of the radius and energy gain proportional to the fifth power, you were only talking about building a device maybe 10 times the radius of the lab device. That's TINY as fusion experiments go, and also compared to fission plants. And the thing is basically a slightly gassy vacuum tube with some magnets in it, i.e. mostly empty space, very little material.

If there are any gotchas you'd have to scale it up about that much to find them. So why go halfway and then build a full-size one when, if it turns out there AREN'T any gotchas you've got an operating power plant on the next step?

His plan was to do two more small prototypes, to get some more solid data than his three-neutron final run and compare two geometries for the final deaign, then go for the gotchas-or-gold. If it works, it gets you to production right away and you didn't spend a dime on yet another intermediate prototype. If it doesn't, you're not out all that much more than if you built some intermediate size that was maybe big enough to find the gotchas.

Suppose there AREN'T any gotchas. Then we get to working fusion power years sooner. Ditto if there are gotchas that only show up at the scale between the intermediate prototype and the full-size design. In either case the time spent on the middle-size below-break-even prototype was wasted.

Baby steps are for people who get their money from researching and will be looking for a new job once things are actually working. Big steps are for people who want to get to the finish line.

Re:Makes perfect sense to me. (1, Insightful)

Anonymous Coward | more than 6 years ago | (#20963021)

Baby steps are for people who get their money from researching and will be looking for a new job once things are actually working. Big steps are for people who want to get to the finish line.

That's a lousy policy. If we gave money to everyone who claimed all they needed was 100 times as much money as they'd ever invested in a project before, we'd be spending several times the GDP of the world on perpetual motion trash.

Which is not to say I don't think the Polywell concept is worthy of further funding, but since it's public money, the group needs to demonstrate progressive successes to get progressively larger funding. He only had questionable evidence that fusion has occurred and he wanted $200 million to jump straight to build a plant big enough for net energy generation. He's where Tokamaks were in the 1960's.

And of course, that's with no data on operating a Polywell reactor at intermediate reaction rates, and therefore no data on how to deal with potential problems like heat transfer and effects on the magnets, fuel poisoning and supply, and materials suitable for sustained operation.

Regardless, it's disappointing to hear about his death. I wasn't following the project closely, but it still came as a surprise.

Re:Makes perfect sense to me. (2, Informative)

Lonewolf666 (259450) | more than 6 years ago | (#20964865)

I agree...

Quote from GP:

In this case he believed he had the scaling laws down. With power proportional to the seventh power of the radius and energy gain proportional to the fifth power, you were only talking about building a device maybe 10 times the radius of the lab device. That's TINY as fusion experiments go, and also compared to fission plants. And the thing is basically a slightly gassy vacuum tube with some magnets in it, i.e. mostly empty space, very little material.

If there are any gotchas you'd have to scale it up about that much to find them. So why go halfway and then build a full-size one when, if it turns out there AREN'T any gotchas you've got an operating power plant on the next step?

His plan was to do two more small prototypes, to get some more solid data than his three-neutron final run ...

Three neutrons is indeed very thin, and from the WB-6 photos on Wikipedia, the coils look like they are about two feet in diameter. That leaves some room for scaling up without moving into a special building.
So I'd recommend to scale it up to something whose parts fit through the door of a normal room, then assemble it in place. Maybe twice the diameter of WB-6, that should leave enough room around the coils to build the vacuum chamber and still be quite affordable.
If Bussard was right about power proportional to the seventh power of the radius, that should give a few hundred (2^7*3 = 384) neutrons where WB-6 gave three. That is something you can derive useful statistics from.

SLASHDOT SUX0RZ (-1, Offtopic)

Anonymous Coward | more than 6 years ago | (#20959753)

_0_
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.|!|
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.cx passes away, goatse continues [goatse.ch]

the real story (3, Funny)

User 956 (568564) | more than 6 years ago | (#20959765)

Dr Bussard, the man behind the Bussard Collector and inventor of the Polywell fusion device, passed away last Sunday in the morning.

He didn't simply pass away. He was a victim of entropy.

Electron losses (5, Interesting)

BlueParrot (965239) | more than 6 years ago | (#20959785)

The catch to these devises appears to be that if you have a strong enough electrostatic field to contain the ions then you will also lose A LOT of high energy electrons (Rider 1995), thus reducing the confinement efficiency. As Rider notes, capturing the escaping electrons to recover their energy may make the scheme feasible for D-T fusion ( there are other issues as well however).

Personally I think stellarators are more promising. For those who don't know stellarators are a bit like Tokamaks, except rather than relying on an electric current in the plasma to create the necessary twist to the magnetic field for confinement, they twist the confinement vessel itself ( a bit like a moebius strip ), making them a lot more stable than Tokamaks, and allowing them to operate continuously (You can't induce a DC current in the plasma so Tokamaks necessarily operate in pulses ). Main problem seems to be that since stellerators have a lot less symmetry than Tokamaks the calculations become more difficult, but if computing power continues to rise this will probably be solveable.

As a bonus stellarators look damn cool ; )
http://www.efda.org/pictures_html/stellarator_schema_and_live.jpg [efda.org]
http://www.psl.wisc.edu/hsx.jpg [wisc.edu]

Re:Electron losses (2, Insightful)

illegalcortex (1007791) | more than 6 years ago | (#20959877)

Wow. Now that's a piece of technology that actually looks as cool or cooler as what the special effects teams rig up for any scifi pic.

Re:Electron losses (3, Interesting)

BlueParrot (965239) | more than 6 years ago | (#20960147)

Of course, you also have the Z machine [sandia.gov] . A bit more wacky, but certainly scores high on my looks-cool-o-meter. :P

Re:Electron losses (1)

11223 (201561) | more than 6 years ago | (#20965503)

That's not a Z-machine. This [homeunix.org] is a Z-machine.

Re:Electron losses (1)

budgenator (254554) | more than 6 years ago | (#20960321)

the idea in the polywell isn't to contain the ions, but to contain the elcetrons, which will attrack the ions.

Re:Electron losses (4, Interesting)

BlueParrot (965239) | more than 6 years ago | (#20960867)

the idea in the polywell isn't to contain the ions, but to contain the elcetrons, which will attrack the ions.


From Maxwell's equations div B = 0, so magnetic field lines cannot suddenly stop, and thus magnetic fields alone cannot confine charged particles in a plasma which has the same topology as a sphere ( a charged particle that travels along a magnetic field line will escape the confinement ). Consequentially you WILL have electrons leaking out of the magnetic mirrors, and this effect will increase as the potential well height increases.

Tokamaks and Stellarators don't have this problem because they are topologically equivalent to a torus, and thus their magnetic field lines can completely enclose the plasma, while simultaneously not penetrating the plasma facing components.

There are further problems with the polywell design. As an example, even at optimal energy levels the reactants will fail to fusion in many of the collisions, and thus the ions will thermalise much quicker than they fuse. Bussard claimed he could avoid thermalisation of the ions, but this is simply not possible in the polywell design since it would require a spontaneous process to transfer energy between the ions in such a way that their overall entropy decreases. While the polywell is not a closed system, and thus not subject to the second law of thermodynamics, there is no meaningful energy input other than the initial potential energy of the ions, and thus for thermalisation to be avoided there would have to be a large entropy flow out of the plasma, and thus it would quickly cool to levels bellow that required for meaningful fusion. In short, you will rapidly get thermalisation of the ions, which in turn leads to X-ray losses from the electrons. If you did heat the plasma, by say injecting microwaves or neutral particle beams, it would still not avoid the problem of thermalisation unless you managed to selectively accelerate the low energy ions, while simultaneously slowing the fast ones ( and of course, if this energy exceeds the fusion power, as it will have to do in order to overcome the speed of thermalisation, then you won't get net energy out of the device ).

While we are at it, no, you are not going to produce a Boron plasma with any significant number density without getting electrons in it, just calculate the electrostatic force you would get on an electron outside the device from 1 mole of boron nuclei and you quickly see that this is absolutely impossible. Even if the proton/electron ratio is just 5/4, Q = N_a, so you are talking roughly 6*10^23 times the proton charge ( or 60 million Coulomb ).

You then have to take into consideration other problems, like sputtering of plasma facing compounds, giving impurities that cool the plasma ( and since all potential plasma facing compounds have Z numbers of 6 or above, this will further increase X-ray losses ). There is no proposed way to design a divertor, so the device could most likely not operate for extended periods of time.

Basically I don't see this getting a confinement time even close to that of a Tokamak or Stellarator. The number density will be dramatically less ( since it is limited by the height of the potential well ), and it just doesn't seem likely you will get even close to the lawson criterion. Granted, you don't need to achieve ignition in order to extract a lot of energy, but you won't get a high value of the nTtau triple product without raising T to very high energies, which impacts the amount of energy you can gain.

Re:Electron losses (1)

matrix0f8h (320909) | more than 6 years ago | (#20961679)

Mod parent up...

Re:Electron losses (1)

budgenator (254554) | more than 6 years ago | (#20961895)

Thanks, I guess that's pretty much "Nuclear Fusion for Dummies"!

Re:Electron losses (0)

Anonymous Coward | more than 6 years ago | (#20962053)

Bussards are neat, and tokamaks and stellarators are neat, and they might even work to some extent. But I think by using energy to fight the forces involved - that it's doing it the hard way. Rather they should look at how magnetism interacts with a moving charge and make it work in their favor...

I'd say to make a plasma follow a path that resembles a slinky curved around with the ends connected so it looks like a donut. (A tightly pitched toroidial helix?) Make sure there are no phyical obstructions on the "hole" in the middle, and neat stuff should happen where the plasma streams bunch together. The tighter you could get the hole in the middle, the better. Maybe twist the donut a bit along the axis going through the hole so you might have a longer path to accelerate the plasma going towards the hole. (Kinda like a spiral when looking straight through the hole.) If something like that works, I'd laugh because it might be simpler to make than what folks would expect. (Charged plasma sheath over donut shaped structure that might be somewhat self organizing once a current flow is induced into it with some thought out and well placed electromagnets.) But I've yet to see any real physicists vouch for or try anything like that.

Re:Electron losses (2, Interesting)

billsoxs (637329) | more than 6 years ago | (#20962235)

Ah but this was the idea behind T-maks. It does not work well because of the endless number of waves that occur as the temperatures ramp up. I remember seeing a high speed film from TFTR - where the plasma hit one of the divertors - it caused a big blob of 'stuff' to fly across the chamber. Big as in baseball size. This stuff hit the inside and exploded there - causing all sort of little bits to fly back the other way.... Not a good thing for a toy that needs excellent cleanliness. I don't think that this was ever published - I wonder why... Don't get me wrong - fusion should be studied - BUT anyone who claims it will be a power source is - or should be - on drugs.

Re:Electron losses (4, Interesting)

KonoWatakushi (910213) | more than 6 years ago | (#20963855)

Instead of producing lengthy expositions about the flaws of technologies that you don't understand, why don't you try learning about them instead? From your post, it is clear that you neither understand, nor have you read any of Dr. Bussard's papers on the subject. Given the topic of this story, you could at least have enough respect to do so, before spreading FUD about ideas.

First of all, no one is claiming that the divergence of a magnetic field is non-zero. The fact is, the "wiffle ball" trapping of electrons in a Polywell is more than adequate for the task. Electrons escaping through the cusps do not equate to losses, as they usually follow the field lines right back into the machine.

In any case, it is highly disingenuous to claim that a Tokamak has no difficulty confining a plasma. While the topology of a Tokamak (or a dipole as in the LDX) may be a better configuration for containing charged particles, this ignores the fact that the ions have a much greater mass. After a number of collisions, it is inevitable that they will smash into a wall. The only solution to this problem is to make the machine bigger, but it is still far from ideal.

Your calculations concerning a Boron plasma are complete nonsense; as described in his recent paper, only a slight deviation (1E-6) from neutrality is necessary to make a well nearly as deep as the drive energy.

Overall, there are at least as many, if not more challenges, in producing a commercially viable Tokamak. I won't discount either approach yet, but the Polywell certainly looks a lot more promising. A quasi-spherical potential well simply seems like a much better place for a sustainable fusion reaction than a divergence-less B field. Wether or not it works out, it certainly deserves more attention and less unfounded condemnation.

Re:Electron losses (2, Interesting)

BlueParrot (965239) | more than 6 years ago | (#20965723)

Instead of producing lengthy expositions about the flaws of technologies that you don't understand, why don't you try learning about them instead?


Well I have seen Bussard's alleged explanation for why he can maintain a non-maxwellian velocity distribution, and quite frankly, it can't work. He seems to argue that there is a spontaneous process in the system which restores the non-maxwellian distribution because the ions thermalise at low energies at the perimeter of the device. However:

a)Restoring a particle distribution to a non-maxwellian energy distribution requires work. It doesn't matter how you do it, if the energy distribution changes towards a more mono-energetic distribution, no matter what the mechanism is, work is required to account for the change in entropy.

b)Because of this a spontaneous process which restores the non-maxwellian velocity distribution must either drain the plasma of energy ( i.e you have large power losses ) or it will require a similarly large input of work.

c)In a p-B plasma you will have a lot of B-B collisions as well as p-p collisions, both of which have neglectable fusion rates and scatter the ions in all directions, and greatly spread their energy distribution. Furthermore, even at optimal energies the p-B collisions have a low fusion probability as compared to the probability for simple scattering.

These three assumptions is enough to calculate the minimum amount of power required to maintain a monoenergetic velocity distribution at a given collision rate and energy. Since the collision rate also determines the rate of fusion at a given ion energy, you thus have a given amount of work required to maintain a monoenergetic energy distribution at a given rate of fusion. To estimate if this is more or less than what is required to make it practical to maintain a mono-energetic velocity distribution, you only need to know the fusion cross section as compared to the scattering cross section, at the given energy. This is exactly what Rider did. The problem is simply that the fusion cross section, even at optimal energies, is very much lower than the cross section for scattering.

Re:Electron losses (2, Interesting)

BCGlorfindel (256775) | more than 6 years ago | (#20973773)

He seems to argue that there is a spontaneous process in the system which restores the non-maxwellian distribution because the ions thermalise at low energies at the perimeter of the device. However:

a)Restoring a particle distribution to a non-maxwellian energy distribution requires work. It doesn't matter how you do it...


And your missing the same thing Rider did. Thermalizing a distribution is just nature. Because of the inherent design of all IEC devices, ions spend >90% of their lifetime in the outer edge of the plasma. That means thermalization is working for maintaining a mono-energetic distribution 90% of the time. Energy isn't being lost, no work is being performed. Energy is just naturally being exchanged between low and high energy ions. Basic high school physics still underly plasma behaviours.

work is required to account for the change in entropy.
Only if your already assuming conditions...
Ions staying in the system naturally thermalize, on average higher energy ions slowing down and lower energy ions speeding up. NO WORK! Ions gaining enough energy from a collision in one pass(or close consecutive passes) to leave the system will be an energy loss. Thermalization works FOR the mono-energetic distribution because of the basic design. Ions spend most of their lives at low kinetic energy thermalizing. A thermalized, maxwellian distribution of ions in the outer edges gives a natural mono-energetic distribution in the core.

Dr. Bussard was so dismissive of Rider's thesis for the same reasons you are putting forward. IEC devices have not previously had a problem maintaining non-maxwellian distributions.

Re:Electron losses (2, Interesting)

BCGlorfindel (256775) | more than 6 years ago | (#20965399)

From Maxwell's equations div B = 0, so magnetic field lines cannot suddenly stop, and thus magnetic fields alone cannot confine charged particles in a plasma which has the same topology as a sphere ( a charged particle that travels along a magnetic field line will escape the confinement ).
Then you've plainly not looked at Bussard's design on even a classical physics level, as he agreed with you. The magnets are held at a high positive potential and electrons are allowed to exit through the cusps and be drawn back in by the positive charge. It's an open re-circulating design and reduces electron losses farther than any mirrored design ever could.

Bussard claimed he could avoid thermalisation of the ions, but this is simply not possible in the polywell design since it would require a spontaneous process to transfer energy between the ions in such a way that their overall entropy decreases.

You mean a spontaneous process to transfer energy from high energy ions to low energy ions? Thermalization will do that for you. The key problem was Nevins suggested losses to a high energy tail that would form. Bussard modelled the thermalization at the edges(where ions spent the vast majority of their time) and found it slowed the maxwellianization long enough. Long enough just means longer than the average ion time to fusion.

Re:Electron losses (4, Informative)

BCGlorfindel (256775) | more than 6 years ago | (#20960429)

The catch to these devises appears to be that if you have a strong enough electrostatic field to contain the ions then you will also lose A LOT of high energy electrons (Rider 1995)

And Bussard insisted that Rider's math model was flat out wrong. Recent experiments by Yoshikawa and MIT have both demonstrated that Rider's model is, in fact, wrong.
The Polywell design has tremendous merit to it and the experiments that Bussard managed at the end of his life were successful in measuring fusion scaling factors and electron loss factors. From those experimental results Bussard's team rushed together what was expected to be their last device in WB-6. On analyzing the data it generated, it achieved record breaking fusion rates. Now that the navy has re-funded his team to finish WB-7, expect to see some big announcements in a year or so.

For more on Polywell theory and background go here. [talk-polywell.org]

Re:Electron losses (2, Informative)

mako1138 (837520) | more than 6 years ago | (#20962041)

I've read Rider's papers and thesis. He basically goes through the various ways of creating a non-Maxwellian electron/ion distribution, and shows that there are significant problems with those concepts. The Polywell is supposed to sidestep those issues rather than proving Rider wrong.

WB-6 ran for a short time and a few neutrons were caught in a detector. The estimated fusion rate is an extrapolation that I am not entirely comfortable with. The statistics simply are not there, nor do I agree with the claim that steady-state operation was reached.

While the Polywell is a fresh concept, it looks like nothing more than a three-dimensional arrangement of magnetic mirrors. I simply don't see how cusp losses can be overcome, nor the collisional dumping of energy from the ions to the electrons. There are lots of things that can go "wrong" in plasmas.

Looking around talk-polywell, the Yoshikawa paper doesn't seem to have much to do with the Polywell (though it's interesting that nobody's measured a double well before).

http://wwwsoc.nii.ac.jp/aesj/division/fusion/aesjfnt/Yoshikawa.pdf [nii.ac.jp]

Re:Electron losses (1)

BCGlorfindel (256775) | more than 6 years ago | (#20965255)

I've read Rider's papers and thesis. He basically goes through the various ways of creating a non-Maxwellian electron/ion distribution, and shows that there are significant problems with those concepts.

I've been through Rider's paper too. He essientially claims that ALL IEC devices of any sort can not maintain a non-maxwellian distribution. However, there is no basis for using the math models of particle distributions that he uses other than that they make the math easier. Read Rostoker .et al for better detail [harvard.edu] than I can provide. The short quote from the abstract follows:
A distribution function like f(v) does not apply to the CBFR, nor to any reactor concept that we are aware of.
Basically calling Rider's model flat wrong, just like Bussard.

If you look closer at Yoshikawa's papers after measuring the double well look close and you will notice he makes mentions of "potential for power generation" in the conclusions of the effects the well has on fusion output.

And as I mention in my prior post, MIT has a very recent paper that also supports Bussard's assertion that non-maxwellian distributions can be naturally maintained. Go here [aps.org] for more. Key quote from it is:
Further, this synchronization appears to modify the particle distribution so as to maintain the non-maxwellian, beam-like energy profile within a bunch.

There has been a resurgence of interest in IEC lately and it's not just Bussard who thought Rider's model and sweeping assertions where just wrong. Considering his stage in life his "fastest" proof was to just build the thing. Unfortunately for him, he didn't even have that much time. If Rider's paper is as bullet proof as many critics claim, why are so many fusion physicists investigating power generation with IEC? Clearly they aught to know better and be familiar with Rider's work. Rider even includes Bussard in his paper's credits because he consulted him for help in getting a model of polywell function. Bussard would have to have been quite nutty/senile to continue his research after Rider "proved" him wrong. Unless of course Bussard understood IEC better than a grad student new to the subject and was right to call Rider's model wrong.

As for the Polywell design:
I simply don't see how cusp losses can be overcome, nor the collisional dumping of energy from the ions to the electrons.
The loses are overcome by using an open, recirculating design. Electrons get out the cusps, and are drawn back in by holding the magnetic coils at a high positive potential. The cusps just need to make the electron density sufficiently higher inside than outside. The outside electrons need a low enough density that they don't arc out. The internal electrons need a high enough density to accelerate ions to fusion speeds. A simple enough design, but Bussard's team wasted a long time trying to design a closed mirroring version which they later demonstrated could never achieve low enough loses. A big reason for testing with non-recirculating designs was the easier engineering since they're budget was so small.

Anything besides Wikipedia?? (0, Flamebait)

sczimme (603413) | more than 6 years ago | (#20959799)


Linking to Wikipedia is sheer laziness. I'm surprised "passed" and "away" weren't Wikipedia links.

Even a simple Google search for (polywell && "dr. bussard") turned up a variety of sources [google.com] , including http://www.talk-polywell.org/ [talk-polywell.org]

Oh ho, someone died (4, Funny)

Anonymous Coward | more than 6 years ago | (#20959803)

Cue the inevitable silly poster who chastises us all for making jokes about someone's death, and the +5 Insightful reply explaining how laughter is a way of coping. Don't forget the meta-comments describing the very phenomenon ;D!

Re:Oh ho, someone died (2, Funny)

Applekid (993327) | more than 6 years ago | (#20959853)

Cue the inevitable silly poster who chastises us all for making jokes about someone's death, and the +5 Insightful reply explaining how laughter is a way of coping. Don't forget the meta-comments describing the very phenomenon ;D!
So, in other words, try to act surprised when it happens?

Re:Oh ho, someone died (1)

Cctoide (923843) | more than 6 years ago | (#20959867)

You need a for-loop in there so people can't get at you for having insufficient metalevels.

Re:Oh ho, someone died (1)

coolGuyZak (844482) | more than 6 years ago | (#20965987)

A for loop doesn't cope with branching all that well. Recursion FTW.

Re:Oh ho, someone died (2, Funny)

Sloppy (14984) | more than 6 years ago | (#20961307)

How dare you trivialize someone's meta-comment?! Someone meta-commented, dammit, and all you can think about is karma whoring. You people make me sick.

Re:Oh ho, someone died (1)

The_mad_linguist (1019680) | more than 6 years ago | (#20964463)

I never metacomment I didn't like.

Oh, wait, goatse, nevermind

Re:Oh ho, someone died (1)

LrdDimwit (1133419) | more than 6 years ago | (#20961899)

I'm dead, you insensitive clod!

Re:Oh ho, someone died (1)

Neoncow (802085) | more than 6 years ago | (#20978693)

Recursive meta-comments are our way of coping.

Mod insightful pleeze. /ducks

may work at lower scales? (3, Informative)

fluffy99 (870997) | more than 6 years ago | (#20960005)

"may work at lower scales than other projects"???? - One of the main reasons for pushing for the WB7 model was that they couldn't get positive net energy at small scales. The prediction was that they'd need something on the size of a standard fission reactor to see viable energy output. Plus, the design team originally modeled all the coils with as a zero thickness circle and couldn't understand that when they built the thing that the coil circle centers had to be spaced apart which caused field losses. After seeing stupid design errors like that, I don't have much faith in the research team, but still the concept is worth investigation.

Re:may work at lower scales? (3, Informative)

BCGlorfindel (256775) | more than 6 years ago | (#20960487)

Plus, the design team originally modeled all the coils with as a zero thickness circle and couldn't understand that when they built the thing that the coil circle centers had to be spaced apart which caused field losses. After seeing stupid design errors like that, I don't have much faith in the research team, but still the concept is worth investigation.

Actually, they initially designed it with permanent magnets and drove the electrons right into the magnets themselves. But the point was to prove electron densities in the center could get high enough for fusion. Regardless of the mistakes made along the way, the got the concept to work for their final tests and expect some big results from the new WB-7 some time next year.

Re:may work at lower scales? (1)

fluffy99 (870997) | more than 6 years ago | (#20962721)

Actually the results from WB-6 were inconclusive and ended with the destruction of one of the models coils before completing testing. The Bussard's team is claiming that fusion briefly occurred during a few of the millisecond-long run times. Peer scientists are all pretty skeptical, claiming the measurement methods were flawed, that their calculations predict much higher losses, the scaling ration isn't r^5, and that the design will never be able to generate a positive flow of usable energy. Without solid data or independent verification of the results, Bussard is still claiming they can skip the intermediate scale testing and go straight to full-scale. The Navy is wisely funding a small-scale version of WB-7 to get better data to determine if the design has merit. If it does, the concept holds a lot of promise. If it's like the other "cold fusion" claims they want to avoid pouring money into a deadend project.

Re:may work at lower scales? (1)

BCGlorfindel (256775) | more than 6 years ago | (#20965291)

Without solid data or independent verification of the results, Bussard is still claiming they can skip the intermediate scale testing and go straight to full-scale.

Bussard never claimed smaller scale tests should be skipped all together. In the google talk he comes off as an academic intent on his field, not a nut. His proposed plan always was the construction of WB-7 and WB-8 devices in ~1 year, but that a committement to the full size device should be made in order to higher good people, since good people don't like 1 year contracts so much. Main thing is his plan always was 2 small scale devices be done first. The push for a full scale device was the scaling rules, which the two smaller devices could prove. With scaling of R^5, the benefit of going full scale were compelling to someone who's been dreaming of this for ages and is near the end of their life.

Re:may work at lower scales? (1)

fluffy99 (870997) | more than 6 years ago | (#20967597)

He claimed he was done with small scale testing and was ready for full-scale testing. His original intent was to prove the scaling with WB-6. WB-7 and WB-8 were the two alternate designs for full-scale. When WB-6 failed before proving his scaling theories (at least to peer review and potential sponsors), WB7 and WB8 were dropped back to small scale designs.

Re:may work at lower scales? (1)

BCGlorfindel (256775) | more than 6 years ago | (#20968485)

His original intent was to prove the scaling with WB-6. WB-7 and WB-8 were the two alternate designs for full-scale. When WB-6 failed before proving his scaling theories (at least to peer review and potential sponsors), WB7 and WB8 were dropped back to small scale designs.

Sorry, you've got your timeline messed up but good. WB-6 was built in a rush when the team's navy funding had already been terminated(as a smaller part of a R&D line item cut). The hope was that it would reduce electron losses as they predicted. From the results they managed to get, that looked to be the case. Because they were shutting the lab down anyways, they decided to push the equipment harder than they knew it could likely handle. A short in the electromagnet coils burned the machine out as a result.
When WB-6 was being built, private funding wasn't even a consideration. Proving scaling theories was performed with many previous designs running with high electron losses to see how fusion power increased as well size grew. WB-7 and WB-8 were only drawn up after Navy funding was gone and Bussard was looking for new money to finish the testing. He stated clearly that he was confident enough he'd prefer to go straight to full scale testing. He repeatedly stated little more information could be gained from more small scale testing. He DID NOT suggest that he was asking for private funding to by pass WB-7 and WB-8. Whether he thought them necessary for the physics or not, he did consider them necessary to mitigate risk for investors.
Luckily for him the Navy re-released his funds to build WB-7. Unluckily, it came to late for him. This of course should be a moot argument in a year when results from WB-7 are available.

Warp Factor 11 (2, Interesting)

digitaldc (879047) | more than 6 years ago | (#20960145)

From the wikipedia article:
In principle, the Bussard ramjet avoids this problem by not carrying fuel with it. An ideal ramjet design could in principle accelerate indefinitely until its mechanism failed. Ignoring drag, a ship driven by such an engine could theoretically accelerate arbitrarily close to the velocity of light, and would be a very effective interstellar spacecraft.

So what would happen to people or computers travelling inside the ship?
Would they move forward through time at accelerated speed? or end up in deep-space oblivion?

Re:Warp Factor 11 (0)

Anonymous Coward | more than 6 years ago | (#20960689)

'Would they move forward through time at accelerated speed? or end up in deep-space oblivion?'

both... unless they hit a star or something...go check that incomprehensible theory of relativity..

Duh!

Read Tau Zero for an extreme answer (spoilers) (2, Interesting)

Explo (132216) | more than 6 years ago | (#20965477)

Tau Zero [wikipedia.org] by Poul Anderson [wikipedia.org] is a good sci-fi story about a ship with a Bussard Ramjet getting really out of hands. Basically, due to an accident the crew of a spaceship are stuck on accelerating forever, fly into intergalactic void, creep ever closer to the speed of light and experience sufficiently serious time dilation to eventually notice that there are no new stars forming anymore, galaxies are getting dimmer as the old stars start to fade away and to top it all, the universe has become old enough to start contracting towards the Big Crunch. (The story doesn't end there, but I'll leave the ending unspoiled)

Godspeed, Doc. (5, Funny)

Anonymous Coward | more than 6 years ago | (#20960179)

.."inventor of the Polywell fusion device, passed away last Sunday in the morning. He leaves behind him 2 long flaming tyre tracks and a mysterious note about Libyans"

Wee, this is very bad. (2, Interesting)

xevioso (598654) | more than 6 years ago | (#20960833)

I read about Polywell about two months ago here. After doing some research on it, I was very much enthusiastic about what I found out and wanted to build a website that would look more professional than the one the polywell folks currently have. At that time, they were still trying to find funding and/or investors, and it was my belief that having a real website, like a lot of energy companies and other places where people have ideas that need funding, would help out. I built one, with the idea that even if they decided not to use it, it would still work as a community forum. I am still trying to get a lot of the information exactly the way I want tit, but the website is here: http://www.xevioso.com/projects/polywell [xevioso.com] Unfortunately, after I sent the message to Dr. Bussard about a month ago to take a look at what I was building, he basically said that while it was a great site, it wasn't going to be useful to them int he near future because of some things coming down the line that would make it unneccesary. Of course, one month later, the Navy resumed funding. And now Dr. Bussard has passed on. In any event, if people would like to get some good information about this project, please visit the link above.

Re:Wee, this is very bad. (0)

Anonymous Coward | more than 6 years ago | (#20961087)

The button donate, where the money go?

And Known Space Cried (1)

Foo2rama (755806) | more than 6 years ago | (#20961375)

The Bushard ramjet is a central piece of technology in Larry Nivin's "Known Space" A universe that encompasses the bulk of Nivins stories. In fact one of the the Halo video game series shares allot of similarities with the Ring World series.

Re:And Known Space Cried (0)

Anonymous Coward | more than 6 years ago | (#20961861)

Not exactly... the structures in Halo aren't ringworlds, they're orbitals.

A Dyson Sphere is a shell of material that surrounds a sun.

A ringworld is a slice of a Dyson Sphere, a ring that surrounds its central sun.

An orbital is considerably smaller, and orbits its star like a planet.

For more info: Iain M. Banks' "Culture" references in Bungie's Halo [bungie.org]

Passed away? Where'd he go? (1)

bataras (169548) | more than 6 years ago | (#20962239)

He "passed away"?? You mean he died, right?

Re:Passed away? Where'd he go? (0)

Anonymous Coward | more than 6 years ago | (#20965549)

You're an arrogant tard with the social skills of a lamprey, right?

I mean, since we're avoiding euphemisms.

Leslie Woods (modeling problems) (1, Interesting)

Anonymous Coward | more than 6 years ago | (#20963089)

I know it is a bit off topic, but seeing as we are discusing confinement, I would love to hear someone comment on Leslie Woods' (a late mathematician from Oxford) equations. Basically, from what I understand from the Nerenberg lecture he gave [apmaths.uwo.ca] , he claimed that the majority of the gap between what the equations predict and what is observed in reality is not due predominantly to missing turbulence, but rather to a missing non-turbulence term.

Unfortunately, from what I understand of what he said, despite his corrected equations predicting very closely what has actually been observed in practise, and turbulence approaches not predicting anything very well beyond their degrees of freedom, the current community (or at least a key subset of it with a lot invested in the turbulence approaches) is uninterested in hearing anything more about it or allowing the work to be published. Apparently they forstall under such issues as demanding it be derived from Boltzmann's equations, despite his objections that this cannot be done due to the fundamental assumptions underlying Boltzmann's equations.

Personally, although I do not have the physics background to comment on the derivation, I must admit that, if the equations are indeed doing a much better job of matching up with what is being observed, I am quite bothered to hear this. I am reminded of such issues as those between Laplace and Fourier regarding the latter's (seminal) work on the Fourier series and the former's repeated objections to it or anything to do with it. Really, shouldn't the final test always be how well it does in the lab? I hate to think of all that great plasma engineering that is being help up over lack of ability to really model these phenomenons well in the lab.

Re:Leslie Woods (modeling problems) (1)

Iowan41 (1139959) | more than 6 years ago | (#20963813)

Thomas Kuhn _The Nature of Scientific Revolutions. Everyone with a college education should read it. Science is a very useful tool, but scientists are people, and behave like people in groups.

This guy dreamed big. (1)

msevior (145103) | more than 6 years ago | (#20965177)

I loved the Niven known space series with the Bussard ramjets.

After reading through the presentation and arguments above I have not no hope that his polywell device will work. I guess we might have more info some time next year.
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