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?
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What has more total heat, your oven at 180C or a tiny decorative light bulb at 2500C?
Temperature is a measure of the thermal energy per molecule, but it doesn’t tell you how many molecules there are or how much total energy is in the system.
Plasma in nuclear tests or scientific experiments can reach phenomenally high temperatures but the total volume of material is very small. The total thermal energy in the system is not significant on a large scale.
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.
Yes, it would, in exactly the same way that rubbing a stick against the ground really quickly would heat the earth. It’s a *technically* true statement yet has no real effect at all because the earth is *really big* and the heat source is extremely small in comparison.
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