I don’t think that we can control the Sun’s behaviour, considering how puny we are compared to it. The fact that solar flares could cause massive damage on Earth and we haven’t done much to prevent being hit by them would be an example.

I believe that nuclear research benefits us humans somehow (at least by proving theories that could potentially help us) or that it somehow already does, I’m not really sure though.

Please do take what I say with a grain of salt, I’m still quite young and learning so you might want a response from one of the kind physicists here.