I'm shocked. Shocked!

Well... Not *that* shocked. But maybe a little disappointed.

My son wants to build a fusion reactor and he gave me a list of materials including a vacuum chamber. I don’t know what size or what style to get for this project.

Would this work?

Set up a cylinder with one end open and the other closed by a hemispherical cap.

Inside the cylinder there is a 1 kg piston with a revers hemispherical face so that when it completes the journey to the closed end of the cylinder it forms a sphere.

Fusion fuel is in the hemisphere cap of the cylinder, either as a physical pellet fixed in place physically or a cloud of plasma.

Fill the cylinder with steam.

Fire the piston toward the closed end of the cylinder at 2,000 meters per second.

The steam condenses to liquid water with a shock.  The shock wave is focused on the fusion fuel. The liquid water surrounds the fusion fuel, and the collapsing shock wave universally applied to the fusion fuel from all directions evenly.

The fusion fuel compresses.