The Shear Viscosity and Thermal Conductivity of Nuclear Pasta

Abstract

We calculate the shear viscosity $\hat{I}\cdot$ and thermal conductivity $\hat{I}º$ of a nuclear pasta phase in neutron star crusts. This involves complex non-spherical shapes. We use semiclassical molecular dynamics simulations involving 40,000 to 100,000 nucleons. The viscosity $\hat{I}\cdot$ can be simply expressed in terms of the height $Z^{\ast }$ and width $\hat{I}”q$ of the peak in the static structure factor $S_p(q)$. We find that $\hat{I}\cdot$ increases somewhat, compared to a lower density phase involving spherical nuclei, because $Z^{\ast }$ decreases from form factor and ion screening effects. However, we do not find a dramatic increase in $\hat{I}\cdot$ from non-spherical shapes, as may occur in conventional complex fluids.

8 pages, 7 figures, minor changes, Phys. Rev. C in press