Do you have a few thousand dollars to spare, some basic machining and welding skills, and the ability to follow directions without getting fingerprints inside your equipment? Then you, too, can build a baby fusion reactor, or fusor, in your garage.
In fact, it’s pretty simple, according to Paul Schatzkin, who runs Fusor.net, a Web site where amateur “fusioneers” congregate to swap equipment and advice: “Find two stainless steel half-spheres, seal them together around a wire grid, suck the air out of it, apply some high voltage to the grid, inject a bit of deuterium into the chamber, and sit back and count the neutrons.” Don’t expect to reach energy breakeven, Schatzkin says, but at least you’ll be failing to achieve practical fusion at only a millionth the cost of a tokamak.
Tokamaks, the multibillion-dollar fusion reactors that have occupied physicists’ attention for more than 50 years in their quest for limitless clean energy, use a magnetic field to confine a plasma heated to about 100 million kelvins and compressed so that the deuterium nuclei inside will collide and fuse. A fusor is even simpler: Just make a very deep electrostatic potential well for your nuclei to fall into, and make it radially symmetrical so that they wallop into each other when they reach the middle [see “Fusioneering” and “Tabletop Fusion”]. Nuclei at a temperature of 100 million kelvins have the same energy as those that have traversed a potential drop of only about 9000 volts, so getting your nuclei to travel fast enough will not be a problem.
The idea comes from Philo Farnsworth, the inventor of the modern television, who, along with Robert Hirsch, built his first fusor in the mid- to late 1960s.