DECAY OF QUANTUM TURBULENCE BY KELVINWAVE CASCADE

Abstract

A study by computer simulation is reported of the behavior of a quantized vortex line at a very low temperature when there is continuous excitation of Kelvin waves with a low wave number. The energy of Kelvin wave is dissipated only at very high wave numbers. It was shown in previous report (Vinen et al. 2003) that nonlinear coupling leads to a net flow of energy to higher wave numbers and to the development of a simple spectrum of Kelvin waves. These results are likely to be relevant to the decay of turbulence in superfluid ⁴He at very low temperatures. To identify the wave number dependence of this spectrum more precisely, we improve the excitation and dissipation method. In this method, the operations of both excitation and dissipation are done in the Fourier space as contrasted with the previous method, whose operations were performed in the real space. The present results are consistent with our previous results not only on the wave number dependence but also on the absolute value. This means the spectrum that we have got is robust one.