Manifestation of infrared instabilities in high-energy processes in non-Abelian gauge theories.

We show that a high-frequency standing wave in SU(2) gauge theory is unstable against decay into long-wavelength modes. This provides a nonperturbative mechanism for energy transfer from initial high-momentum modes to final states with low momentum excitations. The Abelian case does not manifest such instability. Our analysis is supported by lattice simulations.