Global hydrodynamic instability
= Global hydrodynamic instability
= Global instability
{synonym}
A spatially nonuniform system is globally unstable when a <normal mode> satisfying its global spatial <boundary conditions> has positive temporal <growth rate>. This differs from purely local temporal amplification or <convective wave-packet instability>. A locally absolutely unstable region can be necessary without being sufficient for a growing global mode of finite spatial extent.