That doesn't really help me understand how challenging it is. You say that a ring collider would be useless as a fusion energy source. I've never heard of a p

That doesn't really help me understand how challenging it is. You say that a ring collider would be useless as a fusion energy source. I've never heard of a proposal to use a ring collider to create fusion energy, they're for investigating particle physics. So I'm left none the wiser - what am I missing?