Comment Re:So just to avoid misunderstandings... (Score 1) 48
A breakthrough has already happened - ReBCO superconductors. They enable much more powerful magnets, at higher temperatures and lower power levels. This is important for two reasons. 1. It means that a reactor uses much less power to keep itself running, cooling, and operating the magnets that hold the fusion in place. 2. It means the power density of the reactor goes up with the cube of the magnetic field strength. It makes it much much much easier to reach the densities needed to get to break even. There's a Tokomak already being constructed using this type of magnet near Boston, called SPARC. The physics predictions say it will produce 5 times more fusion power than the power used to run it. It is an experimental reactor designed to figure out the last engineering details to make a reactor that actually generates electricity. Its successor (ARC) is well into the design phase, and already has a construction site. ARC is expected to produce 20 times more fusion power than is input, and produce 500MW for the grid.