Submission + - Chinese Fusion Reactor Breaks Plasma Density Limit (futurism.com)
hackingbear writes: Scientists at China’s Experimental Advanced Superconducting Tokamak (EAST) program rang in the new year with a stunning accomplishment: empirical evidence that they used the device to achieve nuclear plasma densities once thought to be beyond human capabilities. To reach a point where fusion reactor can power itself — a sustainable fusion reaction — requires that gnarly plasma to stay hot, dense, and stable for long stretches of time. For years, it was understood that higher plasma densities would inevitably result in instability, collapsing the fuel before it could ignite, a threshold known as the Greenwald limit. In deuterium-tritium fusion, the fuel must be heated to about 13 keV (150 million kelvin) to reach optimal conditions. At such temperatures, the amount of fusion power produced increases with the square of the plasma density. This new research seemingly flips all that on its head. As the EAST team explains, the method basically involves creating a high gas pressure environment in the reactor prior to plasma formation, which allows the plasma to interact with the reactor wall in a much less destructive way than it would otherwise. Scientists also manually pump extra energy into the plasma as it heats, allowing an even rise in density. The result is a plasma that remains stable even as its internal density rises, resulting in fuel densities “far exceeding empirical limits.” While there are still plenty of breakthroughs left before humanity achieves practical power production with fusion, shattering the Greenwald represents a major item on the to-do list — and another notch on China’s lengthy green energy belt.
