Bar-mode instability suppression in magnetized relativistic stars

4th Young Researcher Meeting, Trieste 2013

Franci, L.^1 ; De Pietri, R.^1 ; Dionysopoulou, K.^2 ; Rezzolla, L.^2,3

Dipartimento di Fisica e Scienze della Terra, Università di Parma, INFN, Parma, Italy^1

Max-Planck-Institut für Gravitationsphysik, Albert-Einstein-Institut, Golm, Germany^2

Institut für Theoretische Physik, Frankfurt am Main, Germany^3

关键词: Equilibrium configuration;    General Relativity;    Ideal magnetohydrodynamics;    Mode instabilities;    Poloidal magnetic field;    Relativistic stars;    Toroidal components;    Velocity profiles;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/470/1/012008/pdf
DOI  :  10.1088/1742-6596/470/1/012008

来源: IOP

【 摘 要 】

We show that magnetic fields stronger than about 1015G are able to suppress the development of the hydrodynamical bar-mode instability in relativistic stars. The suppression is due to a change in the rest-mass density and angular velocity profiles due to the formation and to the linear growth of a toroidal component that rapidly overcomes the original poloidal one, leading to an amplification of the total magnetic energy. The study is carried out performing three-dimensional ideal-magnetohydrodynamics simulations in full general relativity, superimposing to the initial (matter) equilibrium configurations a purely poloidal magnetic field in the range 1014-1016G. When the seed field is a few parts in 1015G or above, all the evolved models show the formation of a low-density envelope surrounding the star. For much weaker fields, no effect on the matter evolution is observed, while magnetic fields which are just below the suppression threshold are observed to slow down the growth-rate of the instability.