Superfluid turbulence and pulsar glitch statistics

Abstract

Experimental evidence is reviewed for the existence of superfluid turbulence in a differentially rotating, spherical shell at high Reynolds numbers (Re ≳ 103), such as the outer core of a neutron star. It is shown that torque variability increases with Re, suggesting that glitch activity in radio pulsars may be a function of Re as well. The Re distribution of the 67 glitching radio pulsars with characteristic ages τc ≤ 106 yr is constructed from radio timing data and cooling curves and compared with the Re distribution of all 348 known pulsars with τc ≤ 106 yr. The two distributions are different, with a Kolmogorov-Smirnov probability ≥1-3.9 × 10-3. The conclusion holds for (modified) Urca a..