Astrophysics (index)

Dynamical Instability

(Dynamic Instability)
(situation where a perturbance makes itself larger)

The term Dynamical Instability (or Dynamic Instability, or just Instability) is a condition of dynamical system such that a perturbance encourages its own growth, i.e., a Positive Feedback situation. The term Dynamical suggests occurrence in something is moving, perhaps even before said instability occurs, e.g., conditions producing some periodic motion changing to the point that the Negative Feedback becomes positive. But even in static situations, a change producing instability conditions may be triggering subsequent movement.

In astronomy, the term is common in a number of areas, and undoubtedly could be applied in many more: