As other comments have pointed out, you can’t.

It’s important to notice that this means that the term “ignition” here is misleading. The term is being used to imply that this means some physically important threshold has been reached, but that’s not true.

“Ignition” in this context is simply an arbitrary name for a symbolic point on the reaction efficiency chart. It has no physical meaning. No actual breakthrough in fusion physics has occurred, simply an improvement in efficiency.