Why is it so hard to make a nuclear fusion reactor efficient?

Question

In other words, why is it so hard to get the Q value above 1 (ration between energy output and input)

In: 179

Answer 1

It’s not hard at all. We figured it out back in 1952: the first H bomb have some crazy numbers for the Q value.

Now, if you want to control the reaction in a way such that you can safely use it as a power plant (as opposed to just creating a big bomb), now that is the hard part. You need to drastically reduce the energy output from your reaction (or you get a h-bomb going, which people don’t like), which really hurt your ratios.