Astrophysics (Index)About

dynamical instability

(dynamic instability)
(situation where a perturbation makes itself larger)

The term dynamical instability (or dynamic instability, or just instability) is a condition of dynamical system such that a perturbation encourages its own growth, i.e., a positive feedback situation.

The term dynamical indicates something with movement, often even before the instability occurs: for example, the conditions that produce some periodic motion growing to the point that its negative feedback becomes positive. But I believe the term is also used for conditions that start moving as they become unstable. In astronomy, the term dynamical instability is common in a number of areas, and undoubtedly could be applied in many more:

An example of instability that termed other than dynamical might be a chemical mixture that is out of equilibrium.


(physics,dynamics)
Further reading:
https://en.wikipedia.org/wiki/Instability
https://en.wikipedia.org/wiki/Firehose_instability
https://en.wikipedia.org/wiki/Stability_theory
https://ui.adsabs.harvard.edu/abs/1964ApJ...140..417C/abstract
https://arxiv.org/abs/2206.01755

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