In the Joint European Torus (JET), fusion plasma rushes around the reactor’s core at 150 million °C, hotter than the centre of the sun. Wouldn’t this heat the earth?
In: 2
Sure, but there’s very little at it. Try striking a match. It gets hot, hot enough that you can burn yourself badly on it. But it won’t heat up a room. This isn’t because it’s not hot enough, but simply because it’s a very small object and while the fire is hot, there’s not that much of it.
Similarly, in a fusion reactor you have very very hot plasma, but only a tiny amount of it. It gets hot, and some of the heat leaks into its immediate surroundings (where it will eventually be used to heat water which can then be used to drive a turbine), but it’s not enough to affect a larger areas.
Latest Answers