It appears polywell fusion is still alive and well. First theorized by physicist Harold Grad back in the 50's and pursued by the late physicist Robert Bussard until his death in 2007, polywell fusion could well be the means by which we finally achieve the holy grail in nuclear power: a fusion reaction that generates more energy than it takes initiate fusion, the so-called break even point. Since Bussard's death, other scientists have continued his research.
While not the only approach to fusion, it may well be the least expensive and easiest to build. Two other major fusion efforts, magnetic plasma containment in Europe and laser fusion in the US, have each spent billions trying to achieve the break even point. Polywell fusion, on the other hand, has spent somewhere on the order of double digit millions, with the last funding round of only $12 million provided by the U.S. Navy.
In comparison, Polywell fusion is a bargain-basement technology. It combines two design concepts: One of the concepts involves an unorthodox containment device that's called a Wiffle-Ball, because the magnetic field pattern produced by the reactor looks like the well-known perforated plastic ball. The other concept is the Farnsworth fusor, which uses a high-voltage cage to direct beams of ions to a fusion reaction. Fusor technology is so well-understood that a teenager could do it.A follow-on to Bussard's WB-6 reactor was built – WB-7 – and the results of testing with that device have validated Bussard's WB-6 results. That means that so far, Bussard's calculations have scaled up exactly as he predicted. EMC2 Fusion Development Corporation is now seeking funding to build the WB-8 reactor to continue Bussard's work.
The late physicist Robert Bussard worked for decades to try to show Polywell fusion could work, using a variety of Wiffle-Ball configurations. Just before his death in 2007, he claimed that he was getting close to solving the challenge with his WB-6 device.
Should polywell fusion work as has been theorized, very cheap and safe nuclear power will become available planet wide is short order. The fuel needed is readily available and unlimited. The problem of high level nuclear waste doesn't exist, meaning the threat of nuclear terrorism is greatly reduced. The cost of building a polywell fusion reactor-based power plant will be a small fraction of that of a traditional fission reactor system. They can also build much smaller and more numerous polywell plants, making our electrical grid more decentralized and robust. It could also provide a better means of powering and propelling spacecraft, particularly if joined with another of Bussard's ideas: the Bussard Ramjet, a spacecraft capable of interstellar flight.