Rick Nebel On The Limited Results

For what it's worth:

Here's what we know and what we don't know:

1. We don't have the spatial resolution of the density to see if the cusps are quasi-neutral on the WB-7
2. In one-D simulations the plasma edge (which corresponds to the cusp regions) is not quasi-neutral. Therefore, if the cusps are quasi-neutral it must be a multidimensional effect.
3. Energy confinement on the WB-7 exceeds the classical predictions (wiffleball based on the electron gyro-radius) by a large factor.

Our conclusion is that both the wiffleball and the cusp recycle are working at a reasonable level.

Also getting press elsewhere (Glenn Reynolds among others).

Well, It's Something: Polywell Review Panel Gives Thumbs-Up

From Alan Boyle's Cosmic Log blog, the panel reviewing the results of Dr. Nebel's recent Polywell work:

An EMC2 team headed by Los Alamos researcher Richard Nebel (who's on leave from his federal lab job) picked up the baton from Bussard and tried to duplicate the results. The team has turned in its final report, and it's been double-checked by a peer-review panel, Nebel told me today. Although he couldn't go into the details, he said the verdict was positive.

"There's nothing in there that suggests this will not work," Nebel said. "That's a very different statement from saying that it will work."

By and large, the EMC2 results fit Bussard's theoretical predictions, Nebel said. That could mean Polywell fusion would actually lead to a power-generating reaction. But based on the 10-month, shoestring-budget experiment, the team can't rule out the possibility that a different phenomenon is causing the observed effects.

"If you want to say something absolutely, you have to say there's no other explanation," Nebel said. The review board agreed with that conservative assessment, he said.

The good news, from Nebel's standpoint, is that the WB-7 experiment hasn't ruled out the possibility that Polywell fusion could actually serve as a low-cost, long-term energy solution. "If this thing was absolutely dead in the water, we would have found out," he said.

Polywell Gets Another Crack?

A couple contracts would make it appear that the Navy has decided to pursue Robert Bussard's Polywell design. M. Simon has more at Power And Control.

Update: Apparently stay-alive funding until the Navy decides what to do.

R.A. Nebel On Plasma Calculations

R.A. Nebel writes in the comments section of the MSNBC thread:

In general, some types of plasma theories work pretty well and others not so well. Plasma theories work pretty well for calculating equilibria and global stability. Transport calculations and kinetic calculations are considerably more suspect. The thing that raises the red flags about the collisionality calculations is that when you look at the Chacon work he sees a big difference between square potential wells (as assumed by Nevins) and parabolic potential wells. I would not have expected that result, and that tells me that none of these results are truly "generic". I think this issue has to be resolved experimentally. That's not to imply that these calculations have no value. What they do tell you is that collisions on the boundary are beneficial (they remove angular momentum) while collisions in the core can be a problem. This, of course, was known by Bussard and Krall a long time ago. It's also possible to affect these collision rates by techniques like gas puffing into the boundary (i.e. introducing neutrals).

Also, I would like to thank M Simon, TallDave and their fellow bloggers for their continued interest in this technology. We appreciate that a great deal, but as you might imagine we have been a little too busy to communicate very much with the on-line people.

It makes you wonder just how much could be accomplished with computers, or how little.

R-Squared's Top Energy Stories

Of course, my favorite on the list is number 10:

10. US Navy funds Bussard Fusion

I think you have to include the US Navy funding Bussard Fusion in there:

http://www.defensenews.com/story.php?F=3139619&C=navwar

Bussard died a couple months ago. I had really given up on fusion, but his work actually appears to have a reasonable change to work. Hopefully with more funding his team will be able to make it work.

Yes, Dr. Bussard's work will be carried on. First step is to construct WB-7 and replicate the results achieved with WB-6. Hopefully by the end of April 2008. If that works, then on to WB-8, and then an actual power generating plant.

Number 25 is also pretty interesting:

25. Cooper Pairs in insulators

http://www.aip.org/pnu/2007/split/849-1.html

One of the AIP's top stories of the year, this discovery may well help us reach a better understanding of superconductivity and insulators both. Superconductivity is of course a holy grail in energy research, and while this discovery doesn't directly lead to a room temp superconductor, it does add to the fundamental knowledge of material in the solid state.

Read the whole thing. It's good stuff.

Interesting Bussard Obit In The New Mexican

From the comments in a prior post, Power And Control points to an obituary of Robert Bussard in The New Mexican.

March to May. It's no overstatement to say, as M. Simon does, that "Civilization depends on it."

Congress Garrotes ITER

Zero dollar budget. Sometimes, you just don't know what to say. (Via IEC Fusion Technology.)

Another IEC Fusion Company: Fusion Power Generation

A couple of Columbia grads are having a go at IEC fusion under the name Fusion Power Generation, and they're looking for funding. (Aren't we all?) Alex Klein used to work at EMC2; the meat of his approach can be found on their Q & A page:

9. What is different about our approach?

- By adding a particular type of magnetic field to a traditional spherical IEC machine, using a shaped electromagnet which doubles as the accelerating cathode, we are able to dramatically lower the losses of energetic ions that limit the efficiency of traditional designs.

- The magnetic field confines electrons to the reaction region at the center of the machine; electrons enter via secondary emission from the electromagnet itself. The electrons bulk-neutralize the positive charge of the ions, and allow the ions to converge to very high densities at the center: the density can be increased by a factor of 10,000 or more over conventional IEC devices.

- The magnetic field also creates space charge lenses at the openings of the electromagnet so-called magnetic mirrors, which in turn serve to continually refocus beams of ions as they pass in and out of the core. The focusing action can be made to exactly counteract the effect of Coulomb collisions between particles, and ions can re-circulate on stable orbits thousands of times through the device without colliding with a material structure, preventing the loss of energy that limits the efficiency of conventional machines. In this way the density will be greatly increased while the input power to the device will be reduced over conventional IEC machines.

- Both effects will help solve the problems that have limited previous IEC experiments' performance.

- With higher densities, electrons and ions can arrange themselves in alternating layers of positive and negative charge, forming "virtual electrodes" that can result in yet higher densities of ions at the center of the machine, and a trapped ion population that never intersects any material structure. Evidence for this effect has previously been observed in operating IEC machine.

- The addition of a small radio frequency modulation of the cathode voltage will drive trapped ions to converge simultaneously at megahertz rates in the very center of the machine at high energies, provided a harmonic electric potential can be maintained inside the cathode, an effect called POPS (Periodically Oscillating Plasma Sphere) that has been documented in previous IEC experiments.

- Pulsed operation will potentially raise the fusion rate still further.

- We have plans to extract ions which have developed non-ideal orbits at low energy, thus substantially increasing the energy confinement time and further raising efficiency.

Good luck, guys. (Hat tip: jumartinez at talk-polywell.org.)

Navy Funds EMC2 Efforts

Via Power And Control, the Navy is funding EMC2 Corp. to find out whether Bussard's claims about the WB-6 unit were correct, to the tune of $2M. The Defense News article's physics are a bit off, though:

Bussard received nearly $2 million under a U.S. Navy contract in August to continue work on an inertial electrostatic confinement reactor he had developed. The reactor uses magnetic fields to confine electrons, whose negative charge causes protons and Boron 11 atoms to fuse. The fusion sets off a chain of reactions that produces electricity.

The electrons actually get in the way of the process (see brehmsstrahlung radiation).

What To Do With Those Neutrons? Part 2, Neutron Effects

Interesting citation here indicating that "[f]ew previous studies have shown measurable effects on the mechanical properties of HY-80 steel if irradiation levels are below 1x10¹⁷n/cm²." Nevertheless, it it would be useful to see what kind of radioactive changes the neutrons might induce in said steel. Using the wise-uranium.org calculator, for fast neutrons bombarding 1 kg stainless for a year, we get the following (slightly reformatted):

Neutron flux = 647.0e9  per cm2s
Irradiation = 1 a;  Delay = 0 h 
 
    Original      Reaction      Activation       Half-
    Nuclide                     & Decay (~>)     Life
                                Products

710.0 g Iron:
          Fe-54    (n,3n) ->           Fe-52    (8.275 h)
                                    ~> Mn-52m   (21.40 m)
                                    ~> Mn-52    (5.592 d)
          Fe-54    (n,p)  ->           Mn-54    (312.7 d)
          Fe-54    (n,t)  ->           Mn-52    (5.592 d)
          Fe-54    (n,A)  ->           Cr-51    (27.70 d)
          Fe-56    (n,2n) ->           Fe-55    (2.700 a)
          Fe-56    (n,p)  ->           Mn-56    (2.578 h)
          Fe-56    (n,t)  ->           Mn-54    (312.7 d)
          Fe-57    (n,3n) ->           Fe-55    (2.700 a)
          Fe-57    (n,p)  ->           Mn-57    (1.470 m)
          Fe-58    (n,t)  ->           Mn-56    (2.578 h)

190.0 g Chromium:
          Cr-50    (n,2n) ->           Cr-49    (42.09 m)
                                    ~> V-49     (330.0 d)
          Cr-50    (n,t)  ->           V-48     (15.97 d)
          Cr-52    (n,2n) ->           Cr-51    (27.70 d)
          Cr-52    (n,p)  ->           V-52     (3.750 m)
          Cr-53    (n,3n) ->           Cr-51    (27.70 d)
          Cr-54    (n,t)  ->           V-52     (3.750 m)
          Cr-54    (n,A)  ->           Ti-51    (5.750 m)

100.0 g Nickel:
          Ni-58    (n,2n) ->           Ni-57    (1.503 d)
                                    ~> Co-57    (270.9 d)
 
          Ni-58    (n,3n) ->           Ni-56    (6.099 d)
                                    ~> Co-56    (78.77 d)
          Ni-58    (n,p)  ->           Co-58    (70.81 d)
          Ni-58    (n,t)  ->           Co-56    (78.77 d)
          Ni-58    (n,A)  ->           Fe-55    (2.700 a)
          Ni-60    (n,2n) ->           Ni-59    (75.00e3 a)
          Ni-60    (n,p)  ->           Co-60    (5.271 a)
          Ni-60    (n,t)  ->           Co-58    (70.81 d)
          Ni-61    (n,3n) ->           Ni-59    (75.00e3 a)
          Ni-61    (n,p)  ->           Co-61    (1.650 h)
          Ni-62    (n,t)  ->           Co-60    (5.271 a)
          Ni-62    (n,A)  ->           Fe-59    (44.64 d)
          Ni-64    (n,2n) ->           Ni-63    (100.1 a)

There's a fair number of short-lived isotopes there, which usually means you'll end up with a mess of radioactivity. I'm still working on calculating all the decay products.

A very cranky, opinionated look at this was on talk-polywell, but I missed it earlier.

Update 10/18: Back to our 1 GW reference case, this means radiated power from fast neutrons (just the ¹¹B + α reaction) ends up as

7.3x10¹⁷ neutrons/s * 2.7x10⁶ MeV/neutron * 1.602x10^-19 J/eV = 316 kW

M. Simon suggested that a 500 MW Polywell device would throw off 5 kW of neutrons. I'm not sure how he derives that figure, but I'll ask.

Robert Bussard Passes

Via Slashdot. Also at New Energy And Fuel and Power And Control. I'm speechless.

What To Do With Those Neutrons?

One problem bugging me about so-called aneutronic fusion is the large numbers of neutrons it actually would produce in practice. To illustrate this, let's go back to an earlier post I wrote about a hypothetical 1GW commercial fusion reactor. Remembering that 1 GW = 1 GJ/s

1 GJ/s / (8.6x10⁶ eV/reaction * 1.602x10^-19 J/eV) = 7.3x10²⁰ reactions/s

Per Wikipedia, 0.1% of all fusion reactions would end up creating a neutron anyway from the ¹¹B + α side reaction. (Update 10/17: This ends up being a 2.7 MeV neutron, well over the threshold of a fast neutron, at 1 MeV.) This means that 7.3x10¹⁷ neutrons/s will be generated from the most widely discussed "aneutronic" fuel out there! That's a simply enormous number. Contrast this with reported background radiation at 2,420m above sea level of 65±3 neutrons/cm²*h. (I'm still trying to come up with a neutron flux figure for a commercial fission reactor.) But assuming a completed ICF device is something like 3m (rounding up a bit) in approximate diameter, and that neutrons are sprayed uniformly (this may not be a good assumption), that means you now have to deal with

4*π*(3m)²*1x10⁴cm²/m²*7.3x10¹⁷n/s = 6.46x10¹¹ n/cm²*s

In a fission reactor, you can use regular water to moderate those neutrons. But what do you do with a fusion reactor?

Coming soon in part 2: how this will affect the parts of the fusor itself thanks to this neutron activation calculator.

Update 10/15: A much better nuclide decay calculator at BNL.gov. "Nuclear Wallet Cards Search" seems almost designed to be impenetrable to Google.

New Sidebar Links, And The Determinism Of Pessimism

Three new sidebar links (and some culling of older ones, which I didn't document): IEC Fusion Technology, itself an offshoot of Power And Control, which I linked to about a month ago; and Talk-Polywell, which mostly is a bunch of guys praying Robert Bussard is right and Todd Rider is wrong.

On this subject, FuturePundit recently ran a piece about the former chairman of Shell, Lord Oxburgh, admitting peak oil production will occur within the next 20 years. What was interesting was the ensuing comments section, and in particular, Paul Dietz' comments about Bussard's reactor:

It cannot prevent electron-ion interactions. Let me run you through the argument to illustrate the two horns of the dilemma.

Polywell has a putative central interaction region where the ions are energetic and are to undergo nuclear reactions. This interaction region CANNOT exclude electrons. If it did (assuming it even could), the space charge of the ions would limit the ion density to a low value, preventing anywhere close to practical (let alone the promised 100 MW!) power levels.

So, there are electrons in this region. There are two possibilities: the electrons have energies approaching those of the ions ('hot' electrons) or the electrons are significantly less energetic ('cold' electrons).

In the first case, bremsstrahlung power exceeds fusion power.

In the second case, the rate of energy transfer from the ions to the electrons greatly exceeds fusion power. This power would have to be recovered and reinjected with extremely high efficiency. Rider's thesis, IIRC, showed that if the electron temperature were half that of the ions, the recirculating power would exceed the fusion power by a couple of orders of magnitude.

These two cases overlap; in the intermediate energy case both occur.

Re-reading Todd Rider's doctoral thesis "Fundamental limitations on fusion systems not in equilibrium" (note to self: link off the Polywell Wikipedia page — the damn thing keeps moving), it seems a complex net of impossibilities. Want to use a magnetic trap to keep electrons away from the ions? Then you induce synchrotron radiation. And then there's the thermalization problem, which, as far as I can understand it, means the ions will need so much energy to keep them inside the device that, unless you're very very efficient about getting them back in, you'll lose them to the outside of the box before they have a chance to fuse.

Rider, of course, seems to have gone on to become a biomedical researcher, a choice maybe not surprising considering the hopelessness invested in his doctoral dissertation. Maybe he's right, but I do have to ask a hopefully useful question: what was the role of his thesis advisor was in drawing those conclusions? Overseeing Rider's project was Lawrence Lidsky, a long-time MIT fusion researcher who wrote a seminal 1983 paper entitled, "The Trouble With Fusion". Despairing of ever surmounting the engineering challenges, he gave up on fusion altogether, and one wonders just how much that colored Rider's research and paper.

Contradicting Rider: "Maxwell Don't Live Here" claims to have a bunch of answers to why IEC fusion could actually work, bolstered by some recent research at MIT.

Bussard Gets Another Round Of Funding?

I'm not sure what to make of this thread at talk-polywell.org citing an August 23 post at Power And Control indicating that Robert Bussard's inertial containment Polywell fusion device has been funded; that post itself points to a lengthier New Energy And Fuel post with more details. I'm hopeful but Bussard has himself confessed to misleading people before for the purpose of getting more money for other projects he feels promising. Nevertheless, since this is his pony (and there's talk he's in failing health), it's pretty certain he's going to ride this one. I'm keeping my fingers crossed.

Pointing And Laughing Time: Electron Power Systems

Not for real. Check out also the creation timestamp on the page (05/05/2003 07:49:52 AM) versus the current date at the top of the page, generated thanks to your local clock on your client. Sneaky. At least they're cheap scamsters: they only want $2 million for their seed money...

Bussard Wins More Funding (Or Not)

The Navy has agreed to continue funding Robert Bussard's ICF fusion device. But that's the extent of the good news, as apparently it's much less than the $200M Bussard says he needs to really get the ball rolling; nonetheless, it's a start... or maybe not. This may well be just a false alarm.

Bussard finally put together a real website at emc2fusion.org, too, though it's really only a single page.

Via Slashdot.

Taleyarkhan Back With A Pop

Okay, so I'm stealing a bit of the New Scientist headline, but anyway, it looks like Rusi Taleyarkhan is claiming victory in his battle against charges of scientific fraud or incompentence, launched in 2002 by skeptics of his claims of creating sonofusion. Those charges were remade in 2006 by UCLA grad student Brian Naranjo, who suggested that the neutron flux Taleyarkhan was reading in fact came from improperly stored lab samples of californium. Purdue University investigated, and recently declared Taleyarkhan innocent in any wrongdoing. (Of course, this doesn't mean he isn't sloppy, and the neutrons did come from the californium.) The 2002 work has since been duplicated by Edward Forringer at LeTourneau University in Texas.

There's a much longer New York Times article on the subject with this additional material:

Critics of Dr. Taleyarkhan said other wording in the statement suggested that the university had disregarded concerns and accusations raised by non-Purdue scientists and instead had concentrated on one seemingly small issue: whether it was improper for the professor to have left his name off two scientific papers.

“The Purdue administration apparently narrowly focused the committee’s charge and avoided the question of whether the research was doctored,” said Kenneth S. Suslick, a chemistry professor at the University of Illinois at Urbana-Champaign.

The reason this is apparently important is because Taleyarkhan may have been playing fast and loose with credit in order to make it appear that the earlier alleged duplication of his results were fraudulent because the group that claimed to have reproduced them included, well, Taleyarkhan:

That appears to refer to a July 2005 announcement that two other Purdue scientists had also produced sonofusion. Dr. Taleyarkhan said this represented independent confirmation of his findings.

Others quickly questioned how independent the two scientists — Yiban Xu, a postdoctoral researcher, and Adam Butt, a graduate student — really were. Both were members of Dr. Taleyarkhan’s research group.

Dr. Taleyarkhan maintained that those experiments were performed in early 2004, before the two scientists joined his group, and that he had merely served as a consultant. (Mr. Butt did not join the group until May 2004 and did not participate in the taking of the data reported in the papers.)

Two scientific papers describing the results list Dr. Xu and Mr. Butt as authors, but not Dr. Taleyarkhan. Dr. Taleyarkhan is thanked in the acknowledgments.

If the scope of the inquiry was limited to whether it was unethical for Dr. Taleyarkhan to have left his name off the list of authors, “I guess I’m not overwhelmingly surprised that the committee decided ‘Not proved,’ ” Dr. Suslick said. “But that’s not the real issue.”

And old Taleyarkhan bête noir Seth Putterman returns to the scene:

In a paper published in Physical Review Letters, Dr. Suslick and Seth J. Putterman, a professor of physics at the University of California, Los Angeles, and another persistent critic of Dr. Taleyarkhan, said they had precisely repeated the 2002 experiment. They reported that they found none of the neutrons that would be the telltale sign of fusion and put the upper limit at just one-10,000th of what Dr. Taleyarkhan had reported.

Via Slashdot.

Update 3/2/07: Corrected the link to the NYT story above.

A Back-Of-The-Envelope Calculation

I was reading Ron Bailey's comments on world energy which cites Daniel G. Nocera's Daedalus article in estimating global energy consumption at 102 TW in 2050. After paying the $10 for the full text, it turns out that Nocera gets his figure from the UNDP World Energy Assessment. Since a terawatt is a measure of energy per unit time (specifically, watts per second) that should come in at 3.22x10²¹ Joules, or 3.22 zetajoules, but the 2000 report suggests something more like 1.041 ZJ, which may be because of the confusion over peak versus average capacity.

Anyway, as a thought exercise, I figured it might be interesting to calculate how much boron such a scenario might be required to fuel all that consumption. From the Wikipedia entry on terrestrial fusion reactions:

8.6x10⁶ eV/atom • 6.02x10²³ atom/mol / 10.811x10^-3 kg/mol •
1.602x10^-19 J/eV = 76.7x10¹² J/kg

So that's almost eighty terajoules per kilogram of boron. Pretty sweet. Now, take a look at this:

1.041x10²¹ J / 76.7x10¹² J/kg = 13.6x10⁶ kg

or about 13,500 tonnes of boron annually. (Of course, this doesn't adjust for inefficiencies in the process; just as a guess, assume the whole process is something like 25% efficient, so consumption is more like 54 kt.) According to Roskill, the world is lately using 1.6 Mt of boron annually, which would make this figure well within reach hardly put a dent in world production.

Update 12/1/06: corrected for the error in Avogadro's number, which makes this look even more obscenely desirable. For a 1 GW power plant running at full capacity all year, that means

86400 s/day • 365.24 day/year • 1x10⁹ W = 31x10¹⁵ J

and

31x10¹⁵ J / 76.7x10¹² J/kg / .25 = 1.6 t

One and a half metric tonnes per year. Now I'm all full of boron-lust... can we just get to fusion... please?

Bussard Presents Another Fusion Device

Via Slashdot, Robert Bussard gives a talk about his latest fusion device. He claims to have solved the Bremsstrahlung radiation problem by segregating electrons in a well of some sort while the ions react without them. Supposedly, he was successful in getting "several orders of magnitude" more fusion out of his device than previous inertial confinement fusion devices of its kind (i.e., the Farnsworth-Hirsch fusor. He's looking for $200 million in funding to build a larger device, of which the first $2-5M will be used to rebuild the machine damaged during the last test run.

One Fusion Reactor Problem Down, Only A Million Or So Left

I keed, I keed. New Scientist has an article about researchers who have discovered a way of keeping fusing plasma from bursting out and damaging the reactor walls.

Researchers at General Atomics, a company based in San Diego, California, US, discovered a simple way to prevent ELMs from occurring. By using a separate magnetic coil to induce small perturbations in the reactor's main magnetic field, they found they could bleed off enough of the plasma particles to prevent the ELMs from bursting out. The solution was tested at an experimental reactor based in San Diego called the DIII-D National Fusion Facility.

Now if they could only get to that pesky breakeven point...

Via Slashdot.