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Nordita Astrophysics seminars

Magnetic oscillations of a neutron star crust and interior following a glitch

by C. Anthony van Eysden (Nordita)

122:026 ()


Following a glitch, the crust and magnetised plasma in the outer core of a neutron star are believed to rapidly establish a state of co-rotation within a few seconds by process analogous to classical Ekman pumping. However, in ideal magnetohydrodynamics, a final state of corotation is inconsistent with conservation of energy of the system. We demonstrate that, after the Ekman-like spin up is completed, magneto-inertial waves continue to propagate throughout the star, exciting torsional oscillations in the crust and plasma. The crust oscillation is irregular and quasi-periodic, with a dominant frequency of the order of seconds. Crust oscillations commence after an Alfven crossing time, which is approximately two and a half minutes at the magnetic pole, and are subsequently damped over the much longer viscous diffusion time, ranging from days to months depending on the temperature of the star. Because of their short periods, it is unlikely that the oscillations correspond to any observed phenomena in radio timing data.