9 research outputs found
Mesoscopic pinning forces in neutron star crusts
The crust of a neutron star is thought to be comprised of a lattice of nuclei
immersed in a sea of free electrons and neutrons. As the neutrons are
superfluid their angular momentum is carried by an array of quantized vortices.
These vortices can pin to the nuclear lattice and prevent the neutron
superfluid from spinning down, allowing it to store angular momentum which can
then be released catastrophically, giving rise to a pulsar glitch. A crucial
ingredient for this model is the maximum pinning force that the lattice can
exert on the vortices, as this allows us to estimate the angular momentum that
can be exchanged during a glitch. In this paper we perform, for the first time,
a detailed and quantitative calculation of the pinning force \emph{per unit
length} acting on a vortex immersed in the crust and resulting from the
mesoscopic vortex-lattice interaction. We consider realistic vortex tensions,
allow for displacement of the nuclei and average over all possible orientation
of the crystal with respect to the vortex. We find that, as expected, the
mesoscopic pinning force becomes weaker for longer vortices and is generally
much smaller than previous estimates, based on vortices aligned with the
crystal. Nevertheless the forces we obtain still have maximum values of order
dyn/cm, which would still allow for enough
angular momentum to be stored in the crust to explain large Vela glitches, if
part of the star is decoupled during the event.Comment: 17 pages, 16 figures, 5 table
Superfluidity in the inner crust of neutron stars
We present a mean-field quantum calculation of the specific heat in the inner crust of neutron stars, taking into account the inhomogeneous character of the system, in which a lattice of neutron-rich nuclei coexists with a gas of unbound neutrons
Role of microphysics in the success of type II supernova explosions
info:eu-repo/semantics/nonPublishe
Impact of electro-weak processes in type II supernovae collapse
info:eu-repo/semantics/nonPublishe