Apparently it is also known as “Inertial Electrostatic Confinement Fusion” or “IEC Fusion.” The process is explained on a YouTube video (really more of a PowerPoint presentation, it seems), “IEC Fusion for Dummies.”
See this Democratic Underground thread and links therein. Thomas Ligon will be a discussing it on The Space Show (radio?) tonight (5/8/07) from 7-8:30 Pacific Time – you can listen live by clicking the previous link.
Is this viable, or is it another “cold fusion” red herring?
This sounds suspiciously like a Farnsworth-Hirsch fusor (and looking at the Wikipage I see tha they note that Bussard has done research in this area). The electrostatic fusor is no shady, pseudoscientific scam; it really does fuse deuterium, but not at levels that make it energy positive, much less get close to the Lawson criterion. It suffered from other problems as well, including erosion of the electrode grids, and scaling problems that limited the size at which it could effectively function to nothing more than a tabletop device.
Reading up on Bussard’s Polywell reactor, he’s replaced the grids with an electron plasma which is contained by powerful magnetic fields, which purportedly eliminate erosion problems and, in some manner I don’t understand, reduces the charge accumulation problems that prohibited Hirsch from scaling up his fusor.
Is this pathological science? On one hand, Bussard is a reputable physicst with a doctorate from Princeton. He’s worked in a variety of positions in the field of nuclear propulsion and nuclear fusion, including as an assistant director at the then-Atomic Energy Commission, providing strong support for Tokamak-type magnetic confinement (though he later claimed to have supported T-mag confinement not because he believed it was the best technical approach but because it would be politically viable and would provide funds for “alternate” experiments). On the other hand:[ul][li]Bussard has, in recent years, affiliated himself with some individuals and organizations (see the International Academy of Sciences (Missouri)) that are suspect.[/li][li]Bussard has made a number of egregious calculation and conceptual errors in the past.[/li][li]The p-[sup]11[/sup]B would be essentially aneutronic–that is to say, its output would be almost exclusively charged particles, which makes it much easier to generate electricity directly–but the required temperature is an order of magnitude higher and the power density more than two and a half orders of magnitude lower than D-T reactions, making it substantially more difficult than levels that current confinement systems can achieve even for fractions of a second.[/li][li]Bussard’s estimate of efficiency and energy output is based upon detection of 3 neutrons.[/ul]I don’t think Bussard is out to scam anyone, and it’s certainly possible that he might be on to something significant, but I think the claims that it’s all working, there’s no need or value in an intermediate experimental installation, and that it’ll all be ready for production in a decade (give or take) is somewhat hyperbolic at minimum. [/li]
It would be very cool if it turned out to be a viable avenue to fusion, though. An efficient, scalable aneutronic fusion power generator would solve a lot of problems.
Umm…helium atoms are alpha radiation aren’t they? So not so much radiation free.
Also the higher the atomic number of a nuclei, the harder it is to fuse, thats why most fusion schemes involve hydrogen isotopes. If his magnetic confinement scheme was really possible, I’d think he’d start with something that fused at lower energies.
Also the “International Academy of Sciences” description of the device says that charged particles are attracted along the gradient of an electric field, which seems a kind of elementary mistake for a “Acadmey of Science”.
Don’t know enough to say more, but this is hitting my BS detector pretty hard.
Please tell me how an atomic nucleus can decay into helium atoms without releasing an alpha particle. Even if the alphas are stopped before they hit anything meaningful, it’s not “totally radiation-free”, as per the claim.
Err, fair enough, but then thats another error in the article. Beryllium-8 decays into alpha particles, not He atoms (aren’t all decay products ionized due to the energies involved?)
You are correct that the reaction releases alpha particle radiation. The reaction itself is not truly radiation-free, and I don’t think it’s been claimed as such. It is neutron-free however, which means that the walls of the fusion chamber don’t become radioactive over time like they will with deuterium/tritium fusion. The moment the fusion reaction is switched off the radiation emitted will go to zero. That’s what’s meant by radiation-free.
Releasing most of its energy as alpha particles is actually a good thing. Not only are alpha particles remarkably easy to shield, it’s actually possible to convert the energy in a fast charged particle directly into electric power. If a sustained H-B11 fusion reaction ca be maintained it should be possible to tap an electric current straight off the shielding walls, without any of the intermediate steps of boiling water into steam and using a turbine to power a generator that would otherwise be needed.
The p-[sup]11[/sup]B reaction only releases alpha particles (helium nuclei) with a combined kinetic energy of 8.7MeV. As AndrewL notes, this is actually advantageous, since you can use the moving charged particles directly to generate electricity rather than having to capture them in a fluid medium and use the resulting temperature (and possibly phase) change to drive a boiler and dynamo, with all the corresponding losses and material limitations of a heat engine. Alpha particles, even highly energetic ones, are readily shielded by even a very modest amount of shielding, so the concerns about neutron radiation, which can transmute elements into radioactive isotopes and damage structural materials in a fundamental way (as well as pose a grave risk to living creatures), are reduced. (There is one branch of the p-[sup]11[/sup]B reaction that produces a neutron, but it’s very unlikely, only occuring less than 0.1% of all reactions.)
This is, arguably, the coolest part of this possibility. You cannot imagine how bummed out I was, as a kid, to learn that nuclear power plants worked by heating water (or other substance), rather than some more direct method of generating electricity.
Dr. Bussard, as in, ‘Bussard Ramjet’, is one of the geniuses in fusion. He does not talk bullshit. He works his tail off. He may be wrong, his path may turn out to be not as promising as theory, but he is not anything like Orbo.
I wouldn’t exactly wave around the Bussard ramjet as proof of the genius of its progenitor. There are numerous problems with the fusion ramjet rocket concept, not the least of which is that for any even vaguely realistic exhaust velocity and specific impulse the ramjet sees more drag than thrust. There’s also the difficulty of p-p fusion, espcially with the sparse amount of fuel a field even ten thousand kilometers wide could collect. And never mind that you’ve have to tow any lifesystem well behind and presumably off to the side of the propulsion system to protect the crew from the intense magnetic fields.
However, a compact fusion source would go quite a way to making an interplanetary propulsion system viable, either via direct propulsion or (more likely) some method of ion propulsion.
