Fusion Stirrings

There has been a lot of new work lately on desktop experiments to generate small amounts of nuclear fusion. I wish these folks all the best - it would change life in a fundamental way if it could be made to work on a day-to-day basis.

Pyroelectric devices can be used to create an intense electric field that, in turn, generates a plasma where fusion can occur.

In the UCLA experiment, scientists placed a tiny crystal (of lithium tantalate) that can generate a strong electric field into a vacuum chamber filled with deuterium gas, a form of hydrogen capable of fusion. Then the researchers activated the crystal by heating it.

The resulting electric field created a beam of charged deuterium atoms that struck a nearby target, which was embedded with yet more deuterium. When some of the deuterium atoms in the beam collided with their counterparts in the target, they fused.

And, of course, sonoluminescence has come under greater scrutiny than ever as a way of generating the high temperatures required for fusion (sonofusion).

As soon as Satterwhite pokes the source near the glass cell, the liquid inside starts to sizzle and ping. It sounds something like a pan of water on the stove beginning to boil. The neutrons flying off of the source are tearing very small, almost microscopic, holes in the liquid, or “cavitating” it in the language of the physicists. You can see bubbles appear, flickering around the inside of the jar, most of them concentrated in the center of the liquid, where the sound waves are focused.

The bubbles pop and form, pop and form, over and over again, at 60 kilohertz. Each time, an acoustic wave is ripping the liquid open and then collapsing bubbles even more violently. Imagine smacking a piece of bubble wrap with a hammer. Now imagine hundreds of tiny spherical pistons, hammering away.

What happens inside the bubbles when they collapse still is somewhat mysterious to scientists. But Tessien thinks that the imploding bubbles follow some pretty well-understood physical laws. When gasses are compressed, they heat up. And when a vapor gets hot enough, it glows and gives off heat. In a sonofusion reactor, the gas inside these bubbles is being compressed so violently that it sometimes gives off the tiniest of sparks.

These approaches are different than "cold fusion," which was promoted prematurely by the publicity-conscious University of Utah (a few months before I arrived there, in 1989), leading to embarrassment and a massive loss of reputation.

I wonder if sonofusion and pyroelectrics could be combined? Bubbles trapped in solutions sealed within glass-enclosed squibs suspended between pyroelectric filaments? Hmmm...