The University of Southampton
University of Southampton Institutional Repository

Superfluid neutron star dynamics, mutual friction and turbulence

Superfluid neutron star dynamics, mutual friction and turbulence
Superfluid neutron star dynamics, mutual friction and turbulence
This thesis investigates the role of superfluidity in neutron stars and associated phenomena. We model the internal fluid of a neutron star as a two-component system: one of charged particles and one of superfluid neutrons. We derive a set of multi-constituent hydrodynamic equations that allows for a mutual friction between the constituents. We show that when a velocity difference exists between the two constituents the momentum of each constituent is modified by an entrainment parameter. Throughout all of this work we take direction from both theoretical and experimental work on superfluid Helium. This suggests that a force due to vortex lines in the superfluid acts between the two constituents. The hydrodynamic equations are on a scale at which the effect of vortices can be averaged over. The form of the mutual friction between the two constituents depends on the configuration of the vortices. Firstly, we concentrate on an array of vortices. The mutual friction is calculated both for a straight array, and then extended to a ‘moderately’ curved array. We also investigate a turbulent model for the superfluid neutrons in which the vortices are in a tangle. To include rotation in our model we use a phenomenological approach to construct the mutual friction for a polarised tangle. The hydrodynamic equations are used to investigate how entrainment and mutual friction affect plane waves. We show that there are conditions in which the waves are unstable and discuss how this may lead to turbulence. As a first step in considering the neutron star crust we consider how oscillations in the fluid are dissipated on a boundary. As before, we concentrate on the effects of entrainment and mutual friction. Finally, we consider a simple global model of the glitch phenomenon seen in neutron stars in which the important process is a reconfiguration of the vortex array. We use this model to consider how the observational data may constrain parameters.
Sidery, Trevor Lloyd
0981c40d-27b2-4568-b849-8820239cafb0
Sidery, Trevor Lloyd
0981c40d-27b2-4568-b849-8820239cafb0
Andersson, Nils
2dd6d1ee-cefd-478a-b1ac-e6feedafe304

Sidery, Trevor Lloyd (2008) Superfluid neutron star dynamics, mutual friction and turbulence. University of Southampton, School of Mathematics, Doctoral Thesis, 181pp.

Record type: Thesis (Doctoral)

Abstract

This thesis investigates the role of superfluidity in neutron stars and associated phenomena. We model the internal fluid of a neutron star as a two-component system: one of charged particles and one of superfluid neutrons. We derive a set of multi-constituent hydrodynamic equations that allows for a mutual friction between the constituents. We show that when a velocity difference exists between the two constituents the momentum of each constituent is modified by an entrainment parameter. Throughout all of this work we take direction from both theoretical and experimental work on superfluid Helium. This suggests that a force due to vortex lines in the superfluid acts between the two constituents. The hydrodynamic equations are on a scale at which the effect of vortices can be averaged over. The form of the mutual friction between the two constituents depends on the configuration of the vortices. Firstly, we concentrate on an array of vortices. The mutual friction is calculated both for a straight array, and then extended to a ‘moderately’ curved array. We also investigate a turbulent model for the superfluid neutrons in which the vortices are in a tangle. To include rotation in our model we use a phenomenological approach to construct the mutual friction for a polarised tangle. The hydrodynamic equations are used to investigate how entrainment and mutual friction affect plane waves. We show that there are conditions in which the waves are unstable and discuss how this may lead to turbulence. As a first step in considering the neutron star crust we consider how oscillations in the fluid are dissipated on a boundary. As before, we concentrate on the effects of entrainment and mutual friction. Finally, we consider a simple global model of the glitch phenomenon seen in neutron stars in which the important process is a reconfiguration of the vortex array. We use this model to consider how the observational data may constrain parameters.

Text
Thesis.pdf - Other
Download (1MB)

More information

Published date: March 2008
Organisations: University of Southampton

Identifiers

Local EPrints ID: 66270
URI: http://eprints.soton.ac.uk/id/eprint/66270
PURE UUID: 5c775737-5980-4528-b5c2-138a81efd0a9
ORCID for Nils Andersson: ORCID iD orcid.org/0000-0001-8550-3843

Catalogue record

Date deposited: 27 May 2009
Last modified: 11 Dec 2021 03:24

Export record

Contributors

Author: Trevor Lloyd Sidery
Thesis advisor: Nils Andersson ORCID iD

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×