According to Science, a privately funded company called Tri Alpha Energy has shown success holding plasma in a steady state [sciencemag.org] using a field-reversed configuration [wikipedia.org] machine:
In a suburban industrial park south of Los Angeles, researchers have taken a significant step toward mastering nuclear fusion—a process that could provide abundant, cheap, and clean energy. A privately funded company called Tri Alpha Energy has built a machine that forms a ball of superheated gas—at about 10 million degrees Celsius—and holds it steady for 5 milliseconds without decaying away. That may seem a mere blink of an eye, but it is far longer than other efforts with the technique and shows for the first time that it is possible to hold the gas in a steady state—the researchers stopped only when their machine ran out of juice.
“They’ve succeeded finally in achieving a lifetime limited only by the power available to the system,” says particle physicist Burton Richter of Stanford University in Palo Alto, California, who sits on a board of advisers to Tri Alpha. If the company’s scientists can scale the technique up to longer times and higher temperatures, they will reach a stage at which atomic nuclei in the gas collide forcefully enough to fuse together, releasing energy.
…Facilities like the NIF rapidly implode the plasma, relying on its inward inertia to hold it long enough for a burst of fusion reactions. The ITER, in contrast, holds the plasma steady with powerful magnetic fields inside a doughnut-shaped chamber known as a tokamak. Some of the field is provided by a complex network of superconducting magnets, the rest by the plasma itself flowing around the ring like an electric current.
Tri Alpha’s machine also produces a doughnut of plasma, but in it the flow of particles in the plasma produces all of the magnetic field holding the plasma together.
Might this technique bring nuclear fusion power closer than being perpetually 20 years away?