Yeah, that thought occurred to me, too. You're enclosing a ball of plasma at 100 million degrees inside a containment field that will fail if not kept at 270 degrees below zero. What can go wrong with that?
I feel a cheesy SyFy movie coming on - do they still do those?
A ten-thousand volt glow-discharge in a thin gas near vacuum (very low pressure), generates the misleading 100 million degree label. It really describes the velocity required to obtain a head-on particle collision to achieve operation.