The Effects of Free Vortex Decay in Quasi-Classical and Ultra-Quantum Turbulence

Abstract

Free decay of homogeneous vortex tangle in superfluid has been studied for ultra-quantum and quasi-classical regimes at zero temperature limit. It is found that the decay process is associated with heating by means of phonon generation into the system, even at such a zero temperature limit. An explicit expression for the time evolution of temperature due to the heating has been derived. Such heating affects the motion of vortex strings by (a) decreasing their cyclotron frequencies and (b) shortening their length. This length shortening is a secondary decay process initiated by the primary free decay of vortex tangles. The effect of quasiparticles (phonons) on the wave collapse and energy dissipation of the turbulent states has also been studied through the modulation theory.