So, imagine you have a balloon that you want to blow up. Normally, you would just blow air into the balloon and it would get bigger.
But imagine you wanted to make the balloon even bigger than just blowing in air. You could try squeezing the balloon from outside, but that might not work very well.
Well, a stellarator is kind of like that balloon, but instead of air, scientists try to get very hot gases to expand inside of it. But instead of just squeezing the gases, they use magnets to twist and turn the gases in different directions. It's like they're giving the gases a super complicated maze to follow.
This helps the gases actually stay inside the balloon and not escape. And the twisted path of the gases can actually create a magnetic field that can be used for all sorts of science and engineering experiments.
It's a really cool way to study how things work at the atomic level, and to help us make new technologies that can change the world!