Transitions between turbulent and laminar superfluid vorticity states in the outer core of a neutron star

Details Transitions between turbulent and laminar superfluid vorticity states in the outer core of a neutron star Transitions between turbulent and laminar superfluid vorticity states in the outer core of a neutron star

2006-07-08

arxiv.org/abs/astro-ph/0607161v1

Astrophys.J.651:1079-1091,2006

Astronomy and Astrophysics

Astrophysics

(1) School of Physics, University of Melbourne, Parkville, VIC 3010, Australia. (2) Departamento de Fisica, Escuela de Ciencia

Scientific paper

10.1086/507576

We investigate the global transition from a turbulent state of superfluid vorticity to a laminar state, and vice versa, in the outer core of a neutron star. By solving numerically the hydrodynamic Hall-Vinen-Bekarevich-Khalatnikov equations for a rotating superfluid in a differentially rotating spherical shell, we find that the meridional counterflow driven by Ekman pumping exceeds the Donnelly-Glaberson threshold throughout most of the outer core, exciting unstable Kelvin waves which disrupt the rectilinear vortex array, creating a vortex tangle. In the turbulent state, the torque exerted on the crust oscillates, and the crust-core coupling is weaker than in the laminar state. This leads to a new scenario for the rotational glitches observed in radio pulsars: a vortex tangle is sustained in the differentially rotating outer core by the meridional counterflow, a sudden spin-up event brings the crust and core into corotation, the vortex tangle relaxes back to a rectilinear vortex array, then the crust spins down electromagnetically until enough meridional counterflow builds up to reform a vortex tangle. The turbulent-laminar transition can occur uniformly or in patches; the associated time-scales are estimated from vortex filament theory. We calculate numerically the global structure of the flow with and without an inviscid superfluid component, for Hall-Vinen and Gorter-Mellink forms of the mutual friction. We also calculate the post-glitch evolution of the angular velocity of the crust and its time derivative, and compare the results with radio pulse timing data, predicting a correlation between glitch activity and Reynolds number.

Affiliated with

Also associated with

No associations

Rating

Transitions between turbulent and laminar superfluid vorticity states in the outer core of a neutron star does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Transitions between turbulent and laminar superfluid vorticity states in the outer core of a neutron star, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Transitions between turbulent and laminar superfluid vorticity states in the outer core of a neutron star will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-348183