Energy solutions, one controversy at a time

9 07 2010

Could a DIY fusion reactor solve the world’s energy crisis? Have the billions of dollars invested in fusion research so far been completely misspent?

How could that possibly be true?

Yet this was thrust of a recent BBC article. Engulfed by concerns over journalistic integrity I reeled off a long article about how they need to do better research and put things in context. I even managed to link in a connection to the Science Media Centre of Canada and how that could have helped out on the story.

But, something was eating away at me about the article. Why were they giving so much credence to these people working in their lofts and garages? There had to be more behind it. And there is.

So in a way, while I wasn’t wrong about the angle of the story, I was wrong in my instant dismissal. There is a story within a story.

First and foremost this is a story about technology. While we tend to put science and technology together, they are really quite different beasts. Merriam-Webster defines technology as “the practical application of knowledge especially in a particular area” which I have always seen as development. Science on the other hand, “knowledge as distinguished from ignorance or misunderstanding” (thanks Webster!) is about discovery and organization.

So while there are a few examples of scientists discarding theories that turn out to be right, it isn’t all that common. Peer review is a pretty good, but not perfect, way of establishing which scientific models are better than others.

With technology, we can actually point to many situations where an inferior technology has triumphed over a superior one. VHS vs Betamax is a classic example. The reasons may be economical (one is cheaper than the other) or merely marketing. But my point is clear, with any technology there is room for heading down the wrong development alley. Nobody has crystal ball that will determine the best path to the next generation of technologies.

The technology of nuclear fusion (colliding hydrogen atoms stripped of their electrons together to release energy) has been with us for decades, always tantalizing us with the promise of cheap, clean power. Yet it remains beyond the horizon. While a number of different ways to build fusion plants have been envisioned, the magnetic confinement approach, where superhot gases are confined in a donut shape, or “tokamak”, remains the most prevalent.

Other techniques have been considered. Since the atomic nuclei repulse one another the atoms must be forced together somehow. One possibility is a laser to provide the energy, another is to accelerate them using immensely powerful electric fields. And the second of these possibilities is achievable at home.

This is where things getting interesting for the DIY crowd. The idea is really beautifully simple, even if the practicalities may not be. Take a sphere of wire and give it a negative charge, surround it by another larger sphere with a positive charge. Then if you inject fusionable, positively charged, nuclei into the system they will be accelerated rapidly toward the centre, often passing through the inner sphere whether they may collide with other nuclei and fuse.

Sounds great. Except it isn’t very efficient because most of the time the nuclei actually hit the inner sphere. So if you could somehow create a strong negative charge, without the grid that would be much better. That’s what the researchers have been working on for some time.

You can do this by flipping the charges on the grids around. Rather than having the nuclei collide in the center you can set things up so electrons are accelerated into the middle creating a strong negative charge there. Then you inject your nuclei just inside the positive inner sphere, where they are pulled strongly towards the negative charge and again may collide with another nucleon. But this suffers from the problem of electrons hitting the grid instead of the nuclei.

At this point I’ll mention Dr Robert Bussard. By all accounts he was a brilliant, but “difficult” individual. Famous for suggesting interstellar ramjets which have become popular in science fiction works, his body of research on fusion is prodigious.

His solution to the problem of the electrons hitting the grid was to use magnetic fields. While they are attracted to the charge on the grid, magnetic fields set up within the grid itself can prevent them from getting too close. This design is known as the Polywell. Bussard’s calculations suggested that the amount of power available from fusion scaled up extremely quickly as a function of the size of the reactor – it would grow as the 5th power of the radius! (That seems amazing to me as a physicist, I need to understand more of the details, and some researchers argue that energy losses will prevent this).

The idea was enough for Bussard to start up his own company, EMC2 and get research grants from the US Navy.

Bussard passed away in 2007. But just a few months before, while suffering from cancer, he gave an empassioned presentation to Google to fund research into the Polywell. The video is still available, and it’s been watched by thousands of people. Interest in the technology has definitely been stoked by his presentation.

And the research is progressing still, although there are questions, about what’s actually been achieved and what future funding will be given. EMC2 has developed a series of prototypes and are learning much about this alternative fusion technology. Of course not everyone thinks it will work, and they haven’t been able to build a large prototype yet, but this is a great “underdog” story that deserves some attention. You know, it might just work.

The Polywell is something worth knowing about, DIY fusioneers isn’t the real story here!

(P.S. For another nuclear underdog story, look up Thorium reactors!)

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9 07 2010
Tweets that mention Energy solutions, one controversy at a time « Ecogirl & Cosmoboy's Blog -- Topsy.com

[…] This post was mentioned on Twitter by incognito. incognito said: RT @DrRob_Thacker: Blog post on the world's energy problems and DIY fusion – what's the real story here? http://bit.ly/bFtNel […]

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