Sun in a Bottle (33 page)

Seth Putterman, working at UCLA, came up with an even more innovative way to induce fusion. He and his team created a device whose heart was made of a crystal of lithium tantalate, a compound with a very curious property. It is
pyroelectric
: when you heat it, electrons in the crystal rearrange themselves so that one side of the crystal is positively charged and the other side is negatively charged.
⁸³
Attached to the crystal was a fine tungsten needle. When the researchers heated the lithium tantalate, the crystal’s charges rearranged themselves and ran down the tungsten. The crystal and needle acted as a giant focusing device; all the energy of heating the crystal got turned into an extremely strong electric field right at the needle’s tip.

Putterman and his colleagues put this device—about the size of a coffee can—in a chamber filled with deuterium. When they turned on the heater, the device worked as advertised, creating a huge electric field near the tip of the needle. When a deuterium atom ventured near the tip, the electric field immediately stripped off its electrons and sent the nucleus zooming away at tremendous speed toward a target filled with deuterium. On occasion, the flying deuterium would fuse with one in the target. All in all, the device produced about eight hundred neutrons per second. Again, it was an impressive display and might even lead to a commercial device to produce neutrons; however, it will always consume more energy than it produces. Beams of deuterium nuclei lose energy whenever they strike a target, and on average the amount of energy lost by the deuterium nuclei that don’t fuse will outweigh the energy produced by those that do.

After the cold-fusion debacle, the idea of tabletop fusion seemed impossible—a pipe dream sought after only by cranks. (The first reaction of Michael Saltmarsh, the bubble fusion debunker, upon seeing Putterman’s pyroelectric fusion paper was, “Oh, God, not again.”) But in fact, tabletop fusion—fusion reactions carried out cheaply in a small piece of laboratory equipment—is real, It just isn’t yielding any more energy than it consumes, so it is useless as a source of power.

It is an unfortunate fact of nature: unless you are creating fusion in a hot, dense plasma, you are extraordinarily unlikely to produce excess energy. Too many phenomena conspire against you. Tabletop fusion is an interesting curiosity, but not a path to unlimited power.

I
have been covering fusion since I began my career as a science jouralist, so it is impossible for me to thank all the people who have helped me understand the physics—and the politics—of the fusion quest. To all of them, even to those who might disagree with the conclusions of this book, I give my heartfelt gratitude.

I would also like to thank my editor, Wendy Wolf, as well as Hilary Redmon and Don Homolka for their help with the manuscript. I’m also grateful to my agents, John Brockman and Katinka Matson. My friends and colleagues in the journalism department at New York University have been wonderful to me, and I am grateful for their support. Finally, my friends and family have helped me tremendously. To my parents Burt and Tama, my brother Mark, and of course my wife, Meridith: thank you for everything.