Building a Sun for Us

The U.S. national laboratories really do often have a bad reputation for the not only questionable, but sometimes blatantly unethical things they do. However, you can’t overlook many of the incredible things that emerge from them, either.

Many technologies are developed at our national laboratories that benefit us all. Not only that, but science itself, in nearly all disciplines, is enhanced by their work. With budgets that dwarf most private research organizations, our labs can sometimes procure the resources and brain power sometimes to undertake exotic research that, through any other means, might prove impossible.

As we know, the Sun, our local star, without which we would be frozen and lifeless, is really a titanic nuclear furnace. Composed mostly of hydrogen, the most abundant element in the universe, the Sun draws itself together from this massive cloud of hydrogen, gravity pulling the hydrogen atoms more and more densely, until the hydrogen atoms are under such enormous pressure at the center that the electromagnetic forces that normally keep the atoms far enough away from each other is overcome, and instead, the strong nuclear force takes over which binds two hydrogen atoms into a single helium atom – releasing a lot of energy in this conversion.

So dense and hot at the core, the Sun is able to whiz hydrogen atoms around fast and close enough to keep them colliding and fusing into helium, producing a steady and ongoing reaction.

This is the challenge that many of our scientist are facing right now – creating a viable fusion reaction. Far cleaner than nuclear fission (which splits atoms instead of combining them), fusion power represents a major advance in large-scale energy production that is fairly clean, safe, amazingly efficient, and just plain cool.

The best part is the fuel it uses in the reaction – hydrogen. Clean, abundant, and simple – yet another good reason for large-scale hydrogen production and distribution.

But it’s no so easy to create a star here on earth.

You have to find some way to get hydrogen atoms to overcome their natural repulsion toward each other. You have to get them so energized that they overcome their repulsion and instead bind together, switching to the strong nuclear force. This means getting them very, very close to each other, where nature will just do its thing.

The current mainstream approach to this is superheating an energy plasma – plasma being the forth state of matter, after solid, liquid and gas. In a plasma state, matter is electromagnetically active – they can carry currents and have magnetic fields. Plasma is very hot – the current fusion reactors operating at over 100 million degrees.

Of course, this temperature would melt anything we have to contain it, here on our cold little planet. Luckily, magnetic fields don’t get burt, though – and since plasma is electromagnetic, we can contain it with electromagnetic fields.

This takes a lot of electricity to achieve, though. Currently much more than would be produced by any fusion reaction.

But this is changing. Particularly thanks to the International Thermonuclear Experimental Reactor (ITER) project. Started in 1985 as a joint effort between the US and the Sovient Union, it is now comprised of an internation coalition of countries contributing resources and research to achieving the goal of recreating the Sun, here on Earth.

One of the greatest of the forces coming to the ITER table are the Joint European Torus (JET) people who currently operate the largest fusion research effort around.

And here, in the US, we have Oak Ridge National Laboratory, long involved in fusion research, heading up our contribution efforts to the ITER.

Not to be outdone, MIT’s Plasma Science & Fusion Center is certainly in the works. They have the most powerful containment field in theirs, allowing a much more compact design.

Oh, but back the issues. Once you get the reaction going you have to keep feeding it hydrogen atoms. The new ITER design benefits by keeping the newly-formed helium atoms around in the plasma mix for a while – when the Helium is formed it is very energetic and will help keep the plasma hot, dropping off into a “helium ash” after it’s cooled down a bit (though of course not ash), and removed from the system (escaping the field).

The ITER is a beautiful design. The high-powered neutrons generated by the fusion reaction escape and travel into a lithium “blanket” surrounding the field-contained plasma, absorbing them. It catches the heat, boiling water to turn electrical turbines, and also the neutrons react with the lithium to produce more Tritium (a heavy hydrogen used again to continue powering the plasma) and Deuterium (another hydrogen).

Deuterium is hydrogen (a proton and an electron) but with a neutron in the nucleus as well – effectivly doubling the mass of the atom. Tritium is even heavier, having two neutrons in the atom. This makes for a much higher release of energy.

Not to worry about the safety, either. If containment fails, the reaction stops almost instantaneously – the hydrogen is used up in a flash, and can’t continue, even if more hydrogen were continuing to be pumped into the chamber – there’s just too much space.

So, there we have it – we’re building a Sun. And we’re doing it all together, across boundaries. What a wonderful thing, really. It’s a little strange that we’re doing it so we can boil water – but it’s better than burning coal to do it, or using the more dangerous and toxic fission process.

A little Sun on earth, to boil water. Now that beats war.

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