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Tuesday, 12 October 2010


We all want sustainable energy these days, what with fossil-fuel-induced climate change and the need for nations not to have to rely on dodgy foreigners to sell them the gigajoules they need.

Why don't we use the power of the wind?  I don't mean the pathetic flow of air over our own planet that we already capture with giant versions of children's toy windmills.  I mean an altogether more serious wind:

And I also don't mean capturing its kinetic energy.  That would be far too difficult, and it's not the main source of energy in the solar wind anyway.  The main source of energy in the solar wind is helium-3.   This isotope of helium is particularly suited for use in fusion reactors.  Fusion reactors are attractive because they are potentially very powerful, and because anyone can make one for a few hundred dollars.  Admittedly we haven't yet made one that generates more energy out than you have to feed in, but an abundant source of helium-3 and the combined genius of lots of garden-shed tinkerers might well change all that.

There is almost no helium-3 on Earth.  It has been proposed to mine the Moon for it, as the solar wind embeds it in the lunar regolith.  But the problem with that is that the Moon is a gravity hole that you have to expend energy getting down to, and then expend more getting up from.

Why not put a solar-powered satellite that is, essentially, a big electromagnet at one of the Lagrange points?  The solar wind is ionised, and so it would stream to the satellite's poles, like a mini aurora.

Of course, helium-3 is only a minor component of the solar wind, so it needs to be separated.  But here things start playing to our advantage.  The satellite would use the same technique that mass spectrometers use to produce a clean stream: when you pass an ionised plasma through a magnetic field, the ions deflect through different angles depending on their mass.  All you have to do is to put a collector at the correct angle to the magnetic field for an atomic mass of 3, and the helium isotope you want just falls into it.

If we got everything right, we could provide thousands of amateur fusion researchers with a fuel with real potential, and leave them to collaborate and to compete in the usual crowd-source way to come up with the best design.

And, when they give us our first energy-positive fusion reactor, we would have a non-polluting power source for the entire world that, as it would have been developed on-line by a collective, would be free of patent encumbrance.

Finally consider this: people working on fusion power are, of course, working on building clean power stations.  But — in some cases without realising it — they are also building the human race's first starship engine...

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