General Relativity Seminar
Astrophysical jets: a new numerical approach to force-free electrodynamics
Wednesday August 17, 2016 16:15:00 CEST
Wednesday August 17, 2016 17:45:00 CEST
Dr. Federico Carrasco (CONICET, Ciudad Universitaria Cordoba):
Force-Free Electrodynamics (FFE) is a non-linear system of equations modeling the evolution of the electromagnetic field in the presence of a magnetically dominated relativistic plasma. This configuration arises on several astrophysical scenarios of interest such as pulsars or active galactic nuclei. In this talk, I will present a new numerical implementation of FFE around a Kerr black hole, which reproduce standard results regarding jet formation and energy extraction by means of a truly stationary electromagnetic configuration.
The novelty of our approach is three-folded: i) We use the multi-block technique (1) to represent a domain with S2x R+ topology within a stable numerical scheme. ii) We employ as evolution equations those arising from a covariant hyperbolization of the FFE system (3), which we have developed using the generalized symmetric hyperbolic formalism of Geroch (2). iii) We implement stable and constraint-preserving
boundary conditions, which represents an outer region given by a uniform magnetic field aligned/misaligned with the symmetry axis.
(1) L. Lehner O. Reula and M. Tiglio, Multi-block simulations in general relativity: high order discretizations, numerical stability, and applications, Class.Quant.Grav. 22 (2005), 5283-5322.
(2) R. Geroch, Partial di erential equations of physics, General Relativity, Aberdeen, Scotland (1996), 19-60.
(3) F. Carrasco and O. Reula, Covariant hyperbolization of force-free electrodynamics, Physical Review D 93 (2016), no. 8, 085013.