The reason I’ve been a little quiet these past few days is that I’ve been preparing a talk for presentation at the IEEE International Conference on Plasma Science, held in Baltimore this year. I presented yesterday, and it was generally well received. The topic was technical and boring, so I won’t gn into details here. The talk that ended the session I was at was particularly interesting, though, so I thought I’d blog about it.

The talk in question was presented by J. E. Brandenburg of the Florida Space Institute, titled Microwave Enhancement of Inertial Electrostatic Confinement of Plasma for Fusion: Theory and Experiment. Inertial Electrostatic Confinement (IEC) uses two (or more) nested spherical grids charged to a high relative voltage to accelerate ions towards the common center of the grids, where they collide and fuse. Philo Farnsworth patented an IEC concept he called the Fusor, and there are all the usual conspiracy theories about suppression of his research surrounding the history of the Fusor, though I suspect the truth of the matter has a lot to do with the fact that it didn’t really work very well, at least for power generation.

Continue reading Inertial Electrostatic Confinement Fusion →

I’m a member of a group of young fusion researchers who are trying to figure out how to make fusion happen in our lifetimes. This is nontrivial because ‘young’ in this case means under 40, and current plans from DOE don’t put fusion power on the grid for another 35+ years. Given the accuracy of government forecasts a whole year down the line, I’m not holding my breath.

I think that the single largest factor holding up the development of commercial fusion is not physics, its program structure. We need to revolutionize the way fusion research is structured, and the best way to do that is to bring the power of the market to bear. Prizes have been suggested (notably by Bob Bussard). I offer here an alternative proposal, seeking your feedback.

The goal is to encourage private funding. This means finding a way to reduce the risk to investors in potential fusion schemes. If a given idea can pass a basic peer reviewed sanity check (doesn’t violate any laws of physics), DOE should offer to insulate investors from some measure of risk. As a concrete proposal, say DOE will purchase all the intellectual property assets of any innovative energy company which closes down after raising private venture funding. There would be some limit, indexed to the amount of money raised, say 1/2 the total venture funds raised, up to a limit of $50 million expended by DOE per company. The physical plant would remain property of the investors or creditors. DOE would pay an external auditor to catalog and organize the intellectual property assets, and would make them freely available to interested parties.

There would have to be sensible mechanisms for peer review and for deciding when to shut down (presumably the investors would make that call), but I don’t see showstoppers there. I think the idea would work, but getting congress to agree is likely to be hard. There’s a real danger of the money disappearing after a venture is funded, thanks to diversion to some more worthy cause, like rainforests in Iowa.

Anyway please comment, kvetch, suggest, advise, discuss, either in comments here or in email to me.

Ian Murray (who seems to be having spam problems) should find this one fascinating. There’s a brief, but interesting article in this week’s Economist about the disturbing prevalance of shaky statistics in peer-reviewed scientific papers.

…If a set of data are

I firmly believe that the single most important area of scientific research is cognitive psychology (the rigorous branch of psych, not the motherlovin’ it’s-just-a-cigar-to-me-but-you’re-a-pervert freudian crap). There’s an interesting article on the results of a cross cultural comparison of behavior in some simple games here. This sort of thing helps get at what human nature really is and what’s just cultural overlay. The results are interesting, and generate more questions than answers, but at least the questions are well posed.

btw, welcome back, Rand. I hope the moving problems resolve painlessly.

I came across a rather nice little page on aerodynamics for nonspecialists today. I’ve been slowly teaching myself the basics needed to understand the design of aircraft, and this page provided some good simple background. Plenty of pictures, and clear text.

This was the last day of scientific presentations, and it ended on a high note with a banquet, about which more later. L. J. Perkins did an excellent overview of fusion physics, and mentioned a couple of things in passing that caught my attention. The most significant is that p-B11 is viable as a fuel in fast ignition ICF. In ICF a fuel pellet is compressed by depositing energy symmetrically on a spherical capsule, blowing off the outer layer. The resulting reaction force collapses the pellet to fusion relevant densities, heating in the process. Fast ignition is a scheme where you hit the compressed pellet at or just before the moment of maximum compression with an additional energy source (ion beam or laser) focused on a small spot. Ignition of the fusion fuel is initiated at the spot, and this serves as a spark plug which sends a shock front through the high density fuel, triggering fusion throughout the volume. The nice thing about ICF is that the fuel density is really high, so the mean free path for photons is really short, smaller than the size of the pellet. This means that bremstrahlung, the traditional enemy of p-B11, is less of a problem, since bremstrahlung photons are captured within the pellet, rather than escaping as they do with the lower density plasmas used in magnetic confinement.

Continue reading ICC conference, day 3 →

Today had some fairly cool space related stuff, starting with the first talk of the day, by Alan Hoffman of RPPL. His topic was Field Reversed Configurations, and he mentioned space propulsion as one of the applications. The nice thing about FRCs is that they include open field lines, which means the field lines are not circling the plasma, but exit the fusion device – all magnetic field lines are topologically circles, but there is an important distinction between lines that enclose plasma and ones that do not. Open field lines allow plasma to be expelled, providing propulsion. Obviously this is utterly useless if you don’t have net power gain in the reactor, but hey… Anyway, FRCs are a good candidate for the fusion power core in fusion powered spacecraft, if they ever materialize.

Continue reading ICC highlights, day 2 →

The first day of the ICC conference was pretty much as expected. A bit of schmoozing, renewing contacts, that sort of thing. Today’s sessions were on Magnetic relaxation and confinement, and plasma flow and shear. The overall focus of the conference has shifted slightly since the last one I was at, in 2002. This year is much more science focused, and that’s a good thing. It’s always tempting to focus talks on your own machine and where you want to take it, but in order to move the whole enterprise down the road there has to be communication across groups working on different machines, and there has to be crossfertilization. This means that the focus needs to be on the underlying physics, not the engineering details.

Adil Hassam (one of our Principal Investigators) presented the results from MCX, and there was a fair amount of interest. It’s only been a year and a half since we started getting real results, but already we have enough under our belts to generate a fair amount of interest. It’s becoming increasingly clear that velocity shear stabilizes a wide range of instabilities, and there are now results from machines as diverse as Z-Pinches, Tokamaks, and Mirror Machines all of which show improved stability in the presence of velocity shear.

Eventually the PowerPoints from the talks and posters will be put up on the ICC2004 website, but I just checked and there’s nothing there yet. When they are put up I’ll try to remember to post a pointer – Paul Bellan of Caltech had a really cool movie in his presentation showing plasma current filaments merging, kinking, and pinching off to form a spheromak (essentially a plasma “smoke ring”).

Obviously I have net access here in Madison, though it’s excruciatingly slow.

Rand’s post below reminds me of an idea I had a while back, and which has a little bit of traction in the fusion community (though I think it’s had multiple independent inventors). The basic idea is to make a virtue of the neutrons produced in D-T or D-D fusion by using them to transmute nuclear waste into short lived (high radioactivity) isotopes. The isotopes could then be stored while they decay into something (relatively) stable. The benefits are many. First of all it deals with fission waste, helping to remove one of the obstacles to widespread deployment of fission power. Secondly, it doesn’t require break-even from the fusion reactor, which makes everything a heck of a lot easier. The net transmutation plant power balance is now the sum of the fusion power and the power produced by the decay of the transmuted isotopes. A transmutation plant might plausibly be fully self sustaining. Once fusion reactors are in the hands of capitalist captains of industry, they will get better, cheaper, and more reliable.

A more exciting option is a mature fission-fusion hybrid cycle in which there are multiple passes of fission fuel through the reactor wall, to generate power using a set of reactions which spits out very low activity waste, cutting the initial fission reactor part entirely out of the cycle. This, it seems to me, is the logical long-term consequence of getting the evolutionary driving force of the markeplace to bear on the problem of commercial fusion. In the very long term, of course, we will likely see pure fusion power plants, but the path there must be along a sequence of evolvable reactor designs, each of which is at least marginally profitable.

More tomorrow, when the conference proper starts.

Via SciTech Daily, a company called BioTime is making progress in freezing tissues and restoring them to life. They’ve taken tissue to below freezing and restored it to vitality for implantation, and revived whole animals after two hours of clinical death at 35 degrees Fahrenheit. I think that if cryosuspension ever becomes really practical it will emerge out of research like that conducted by BioTime. They are working on extending time under the knife for surgery, but the limiting case of that is days, and perhaps eventually weeks under the knife as the surgical team hunts down and fixes problems, perhaps maintaining different parts of the body at different temperatures so that some organs can heal after surgery while other areas are kept cryosuspended while being operated on. For pursuing really aggressive cancers this might be the way to ferret out the last little metastases.

I’m a little bit of a cryonics skeptic, but open minded to the possibility that revival of people from a natural death might be possible. Much more probable is that people near death can be cryosuspended while alive, and kept on ice until either a cure is found or some contractual criterion requires their revival. The obstacles to freezing a person while alive are currently regulatory (since the cryonicist would be charged with murder, even if it’s a whole-body thing as opposed to just the head). If it becomes clear that people can be frozen and then revived the legal obstacles to preemptive cryopreservation will be much lower. Sadly, there will always be busybodies who will try to interfere, but chances are good that they will be a minority once enough of the population are only a couple degrees of separation from someone who has had surgery while chilled to the point of (what we now call) clinical death. I just hope it happens before I catch anything really nasty 🙂