eli5: once we are able to sustain a fusion reaction, it is supposed to be a self sustaining process (so I have read). How would we be able to “switch off ” this process, and wouldn’t a self sustaining process be an example of a perpetual process?

Question

eli5: once we are able to sustain a fusion reaction, it is supposed to be a self sustaining process (so I have read). How would we be able to “switch off ” this process, and wouldn’t a self sustaining process be an example of a perpetual process?

In: 4

Answer 1

Simple – you stop the flow of fuel. Think about a motor on a car. Once you turn the engine on, the engine stays on until you turn it off right? In that respect, it’s a “self-sustaining” process. But car engines need fuel. Cut off the fuel and the engine shuts down.