6533b828fe1ef96bd128861e
RESEARCH PRODUCT
Transition to ballistic regime for heat transport in helium II
Michele SciaccaMichele SciaccaDavid JouDavid JouAntonio Sellittosubject
Quantum turbulenceGeneral Physics and Astronomychemistry.chemical_elementFOS: Physical sciencesQuantum turbulencelaw.inventionSuperfluidityPhysics::Fluid DynamicsSuperconductivity (cond-mat.supr-con)Ballistic phononsThermal conductivityThermal conductivity; Liquid helium; Quantum turbulence; Micropores; Quantized vortices; Ballistic phononslawMesoscale and Nanoscale Physics (cond-mat.mes-hall)Settore MAT/07 - Fisica MatematicaHeliumLiquid heliumPhysicsMicroporesCondensed Matter - Mesoscale and Nanoscale PhysicsCondensed matter physicsLiquid heliumTurbulenceCondensed Matter - SuperconductivityMicroporeQuantized vorticeschemistryHeat fluxThermal conductivityQuantized vorticeSuperfluid helium-4description
The size-dependent and flux-dependent effective thermal conductivity of narrow capillaries filled with superfluid helium is analyzed from a thermodynamic continuum perspective. The classical Landau evaluation of the effective thermal conductivity of quiescent superfluid, or the Gorter-Mellinck regime of turbulent superfluids, are extended to describe the transition to ballistic regime in narrow channels wherein the radius $R$ is comparable to (or smaller than) the phonon mean-free path $\ell$ in superfluid helium. To do so we start from an extended equation for the heat flux incorporating non-local terms, and take into consideration a heat slip flow along the walls of the tube. This leads from an effective thermal conductivity proportional to $R^2$ (Landau regime) to another one proportional to $R\ell$ (ballistic regime). We consider two kinds of flows: along cylindrical pipes and along two infinite parallel plates.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2014-05-12 |