Heteroclinic orbit

The phase portrait of the pendulum equation x″ + sin x = 0. The highlighted curve shows the heteroclinic orbit from (x, x′) = (–π, 0) to (x, x′) = (π, 0). This orbit corresponds with the (rigid) pendulum starting upright, making one revolution through its lowest position, and ending upright again.

In mathematics, in the phase portrait of a dynamical system, a heteroclinic orbit (sometimes called a heteroclinic connection) is a path in phase space which joins two different equilibrium points. If the equilibrium points at the start and end of the orbit are the same, the orbit is a homoclinic orbit.

Consider the continuous dynamical system described by the ordinary differential equation Suppose there are equilibria at Then a solution is a heteroclinic orbit from to if both limits are satisfied:

This implies that the orbit is contained in the stable manifold of and the unstable manifold of .