1,280 research outputs found
Magnetized, Relativistic Jets
Extragalactic relativistic jets are composed by charged particles and
magnetic fields, as inferred from the synchrotron emission that we receive from
them. The Larmor radii of the particles propagating along the magnetic field
are much smaller than the scales of the problem, providing the necessary
coherence to the system to treat is as a flow. We can thus study them using
relativistic magnetohydrodynamics. As a first step, we have studied the
structure of steady-state configurations of jets by using numerical
simulations. We have used a helical field configuration and have changed
different relevant parameters that control the way in which the energy flux is
distributed in jets (namely, the proportion of the energy flux carried by
internal, kinetic or magnetic energy). Our results show significant differences
among the different kinds of jets. Finally, we also report on results based on
synthetic maps of our simulated jets.Comment: Submitted for publication in Proceedings of Science, as contribution
to the proceedings of the XII Multifrequency Behaviour of High Energy Cosmic
Sources Workshop, held in Palermo, 12-17 June 201
La industria de la nieve en las montañas alicantinas
En número dedicado a: La provincia de Alicant
On the convexity of Relativistic Ideal Magnetohydrodynamics
We analyze the influence of the magnetic field in the convexity properties of
the relativistic magnetohydrodynamics system of equations. To this purpose we
use the approach of Lax, based on the analysis of the linearly
degenerate/genuinely non-linear nature of the characteristic fields. Degenerate
and non-degenerate states are discussed separately and the non-relativistic,
unmagnetized limits are properly recovered. The characteristic fields
corresponding to the material and Alfv\'en waves are linearly degenerate and,
then, not affected by the convexity issue. The analysis of the characteristic
fields associated with the magnetosonic waves reveals, however, a dependence of
the convexity condition on the magnetic field. The result is expressed in the
form of a generalized fundamental derivative written as the sum of two terms.
The first one is the generalized fundamental derivative in the case of purely
hydrodynamical (relativistic) flow. The second one contains the effects of the
magnetic field. The analysis of this term shows that it is always positive
leading to the remarkable result that the presence of a magnetic field in the
fluid reduces the domain of thermodynamical states for which the EOS is
non-convex.Comment: 14 pages. Submitted to Classical and Quantum Gravit
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