ignition condition

Ignition, in the context of physics, refers to the point at which a self-sustaining reaction begins. For nuclear fusion, this requires achieving a sufficiently high plasma temperature and confining the plasma so that the energy released by fusion reactions maintains its temperature against energy loss. This balance between heating and energy loss is known as the ignition condition.1

Combustion also requires ignition, which is initiated by external factors like heat or sparks, causing the mixture to reach its ignition temperature. At this point, the reaction spreads, with each burning layer igniting the next. The complexity of these reactions makes it difficult to predict phenomena over wide temperature and concentration ranges, often relying on empirical expressions.2