ASYMPTOTIC STRUCTURE OF POYNTING-DOMINATED JETS

By Y. Lyubarsky. 2009

139 citations recorded by the source corpus.

In relativistic, Poynting-dominated outflows, acceleration and collimation are intimately connected. An important point is that the Lorentz force is nearly compensated by the electric force; therefore the acceleration zone spans a large range of scales. We derived the asymptotic equations describing relativistic, axisymmetric magnetohydrodynamic flows far beyond the light cylinder. These equations do not contain either intrinsic small scales (like the light cylinder radius) or terms that nearly cancel each other (like the electric and magnetic forces); therefore they could be easily solved numerically. They also suit well for qualitative analysis of the flow and, in many cases, they could even be solved analytically or semianalytically. We show that there are generally two collimation regimes. In the first regime, the residual of the hoop stress and the electric force is counterbalanced by the pressure of the poloidal magnetic field so that, at any distance from the source, the structure of the flow is the same as the structure of an appropriate cylindrical equilibrium configuration. In the second regime, the pressure of the poloidal magnetic field is negligibly small so that the flow could be conceived as composed from coaxial magnetic loops. In the two collimation regimes, the flow is accelerated in different ways. We study in detail the structure of jets confined by the external pressure with a power-law profile. In particular, we obtained simple scalings for the extent of the acceleration zone, for the terminal Lorentz factor, and for the collimation angle.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/022e1700b0cee5718369a063ff2f8f3d93513826

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Citations in the corpus

Relativistic MHD simulations of core-collapse GRB jets: 3D instabilities and magnetic dissipation (2015, background): “On the analytic front, Lyubarsky (2009, 2011) obtained steady state solutions to the structure of collimated Poynting dominated jets.”
Three-dimensional magnetohydrodynamic simulations of the Crab nebula (2013, methodology): “Although claims have been made that ideal MHD acceleration mechanisms can provide the required energy conversion (e.g. Vlahakis 2004), it has now become clear that this is not the case (e.g. Komissarov et al. 2009; Lyubarsky 2009, 2010).”
Relativistic Jets Shine through Shocks or Magnetic Reconnection (2015, background): “…flow to relativistic speeds but, generally, magnetohydrodynamic (MHD) models predict that the largest fraction of the energy remains locked in the magnetic field, i.e., the jet arrives Poynting-dominated atthe dissipation distance (Tchekhovskoy et al. 2009; Komissarov et al. 2009; Lyubarsky 2009).”
EFFICIENCY OF MAGNETIC TO KINETIC ENERGY CONVERSION IN A MONOPOLE MAGNETOSPHERE (2009, unknown): “The radial and angular scalings in equation (46) agree with the analytic expectations (Beskin et al. 1998; Lyubarsky & Eichler 2001; Lyubarsky 2009).”
THE STRUCTURE OF THE M87 JET: A TRANSITION FROM PARABOLIC TO CONICAL STREAMLINES (2011, background): “For a general (non-self-similar) case,b > 2 is allowed in 1 The original value is replaced by taking into account of the mass difference of SMBH. analytical and numerical models (Tchekhovskoy et al. 2008; Lyubarsky 2009; Komissarov et al. 2009).”
Kinematics of the jet in M 87 on scales of 100–1000 Schwarzschild radii (2016, methodology): “In general, evolution of the confining pressure can be approximated by a power law: Pext = P0z−κ (14) Lyubarsky (2009) found two different collimation and acceleration regimes for the jet, depending on specific ranges of the power index κ.”
The limb-brightened jet of M87 down to the 7 Schwarzschild radii scale (2018, methodology): “However, this condition can be satisfied only in the “far-zone” where the toroidal field is substantially stronger than the poloidal field (e.g., Komissarov et al. 2007, 2009; Lyubarsky 2009).”