Generation of strong magnetic fields in neutron stars driven by the parity violating electron-nucleon interaction

by Maxim Dvornikov (Pushkov Institute Moscow & Tomsk State University)

Monday 8 Aug 2016, 16:30 → 17:30 Europe/Berlin

seminar room2, building 2A (DESY Hamburg)

Magnetars are neutron stars with extremely strong magnetic fields B > 10^15 Gauss. Although there are numerous models which predict the generation of such magnetic fields, the question of the origin of magnetic fields in magnetars is still open. I put forward a new model for the generation of strong magnetic fields in magnetars based on the magnetic field instability in dense nuclear matter of a neutron star consisting of electrons and nucleons interacting by the electroweak forces, which are parity violating. I start with reminding the general properties of neutron stars and magnetars. Then I give a brief overview of some of the existing models for the generation of magnetic fields in magnetars. I also discuss the main ingredients of our model: the chiral magnetic effect, the Chern-Simons theory in the presence of the electroweak interaction as well as the magnetic helicity. Then I derive the system of kinetic equations that are used to describe the generation of magnetic fields in magnetars. In our model, we predict the amplification of the seed magnetic field B_0 = 10^12 Gauss, typical for pulsars, up to the values ​​observed in magnetars. The scale of magnetic fields predicted in our model is comparable with the radius of a neutron star. The growth time of the magnetic field, 10^3 - 10^5 years, is close to ages of young magnetars. Our model also predicts the generation of maximal helicity for magnetic fields, which were non-helical initially. In addition, I consider the possible energy source providing the growth of the magnetic field. Some open questions arising in the proposed model are also discussed.