AN UNSTABLE SUPERFLUID STEWARTSON LAYER IN A DIFFERENTIALLY ROTATING NEUTRON STAR
C Peralta, A Melatos
ASTROPHYSICAL JOURNAL LETTERS | IOP PUBLISHING LTD | Published : 2009
Experimental and numerical evidence is reviewed for the existence of a Stewartson layer in spherical Couette flow at small Ekman and Rossby numbers (E ≲ 10-3, Ro ≲ 10-2), the relevant hydrodynamic regime in the superfluid outer core of a neutron star. Numerical simulations of a superfluid Stewartson layer are presented for the first time, showing how the layer is disrupted by nonaxisymmetric instabilities. The unstable ranges of E and Ro are compared with estimates of these quantities in radio pulsars that exhibit glitches. It is found that glitching pulsars lie on the stable side of the instability boundary, allowing differential rotation to build up before a glitch. © 2009. The American As..View full abstract
We acknowledge the support of the Max-Planck Society (Albert-Einstein Institut) and the computer time supplied by the Victorian Partnership for Advanced Computation. We thank Rainer Hollerbach for indicating the importance of the Stewartson layer and very illuminating discussions. This work made use of the ATNF Pulsar Catalogue (http://www.atnf.csiro.au/research/pulsar/psrcat; Manchester et al. 2005).