Protoneutron star dynamos: pulsars, magnetars, and radio-silent X-ray emitting neutron stars

Abstract

We discuss the mean-field dynamo action in protoneutron stars that are subject to instabilities during the early evolutionary phase. The mean field is generated in the neutron-finger unstable region where the Rossby number is $\sim 1$ and mean-field dynamo is efficient. Depending on the rotation rate, the mean-field dynamo can lead to the formation of three different types of pulsars. If the initial period of the protoneutron star is short, then the generated large-scale field is very strong ($>3\times 10^{13}$G) and exceeds the small-scale field at the neutron star surface. If rotation is moderate, then the pulsars are formed with more or less standard dipole fields ($<3\times 10^{13}$G) but with surface small-scale magnetic fields stronger than the dipole field. If rotation is very slow, then the mean-field dynamo does not operate, and the neutron star has no global field. Nevertheless, strong small-scale fields are generated in such pulsars, and they can manifest themselves as objects with very low spin-down rate but with a strong magnetic field inferred from the spectral features.

arXiv comment4 pages, 2 figures, to appear on A&A

References in corpus (9)

• Thermal structure and cooling of neutron stars with magnetized envelopes
• PSR J1847-0130: A Radio Pulsar with Magnetar Spin Characteristics
• Mean-field dynamo action in protoneutron stars
• Protoneutron star dynamos and pulsar magnetism
• Convection in protoneutron stars and the structure of surface magnetic fields in pulsars
• Differential rotation of main sequence F stars
• Convective instability in proto-neutron stars
• Joule heating and the thermal evolution of old neutron stars
• The proto--neutron--star dynamo -- viability and impediments

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