Publication date: Jun 2016
Abstract:
We study electrically charged perfect fluid toroidal structures
encircling a spherically symmetric gravitating object with Schwarzschild
spacetime geometry and endowed with a dipole magnetic field. The work
represents a direct continuation of our previous general-relativistic
studies of electrically charged fluid in the approximation of zero
conductivity, which formed tori around a Reissner-Nordström black
hole or a Schwarzschild black hole equipped with a test electric charge
and immersed in an asymptotically uniform magnetic field. After a
general introduction of the zero-conductivity charged fluid model, we
discuss a variety of possible topologies of the toroidal fluid
configurations. Along with the charged equatorial tori forming
interesting coupled configurations, we demonstrate the existence of the
off-equatorial tori, for which the dipole type of magnetic field seems
to be necessary. We focus on orbiting structures with constant specific
angular momentum and on those in permanent rigid rotation. We stress
that the general analytical treatment developed in our previous works is
enriched here by the integrated form of the pressure equations. To put
our work into an astrophysical context, we identify the central object
with an idealization of a nonrotating magnetic neutron star.
Constraining ranges of its parameters and also parameters of the
circling fluid, we discuss a possible relevance of the studied toroidal
structures, presenting along with their topology also pressure, density,
temperature and charge profiles.
Authors:
Kovář, Jiří; Slaný, Petr; Cremaschini, Claudio; Stuchlík, Zdeněk; Karas, Vladimír; Trova, Audrey;