Meaning of Lawson criterion

Law'son crite"rion

Pronunciation: [key]
— Physics. Physics.
  1. (in a hypothetical nuclear fusion reactor) the requirement that in order for the energy produced by fusion to exceed the energy expended in causing the fusion, the product of the density of the fuel and the time during which it is confined at that densitymust be greater than a certain number that depends on the kind of fuel used.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.