Experimental and theoretical evidence of universality in superfluid vortex reconnections

• 成果类型: Article
• 署名作者: Stasiak, Piotr Z.; Xing, Yiming; Alihosseini, Yousef; Barenghi, Carlo F.; Baggaley, Andrew; Guo, Wei; Galantucci, Luca; Krstulovic, Giorgio
• 署名单位: Newcastle University - UK; State University System of Florida; Florida State University; State University System of Florida; Florida State University; Florida A&M University; Lancaster University; Centre National de la Recherche Scientifique (CNRS); Universite Cote d'Azur; Observatoire de la Cote d'Azur
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-13129
• DOI: 10.1073/pnas.2426064122
• 发表日期: 2025-05-22
• 关键词: turbulence; DYNAMICS

摘要

The minimum separation between reconnecting vortices in fluids and superfluids obeys a universal scaling law with respect to time. The prereconnection and the postreconnection prefactors of this scaling law are different, a property related to irreversibility and to energy transfer and dissipation mechanisms. In the present work, we determine the temperature dependence of these prefactors in superfluid helium from experiments and a numeric model which fully accounts for the coupled dynamics of the superfluid vortex lines and the thermal normal fluid component. At all temperatures, we observe a pre-and postreconnection asymmetry similar to that observed in other superfluids and in classical viscous fluids, indicating that vortex reconnections display a universal behavior independent of the small-scale regularizing dynamics. We also numerically show that each vortex reconnection event represents a sudden injection of energy in the normal fluid. Finally we argue that in a turbulent flow, these punctuated energy injections can sustain the normal fluid in a perturbed state, provided that the density of superfluid vortices is large enough.