Relativistic Magnetohydrodynamics with Application to Gamma-Ray Burst Outflows. I. Theory and Semianalytic Trans-Alfvénic Solutions

By Nektarios Vlahakis, A. Königl. 2003

183 citations recorded by the source corpus.

We present a general formulation of special relativistic magnetohydrodynamics and derive exact radially self-similar solutions for axisymmetric outflows from strongly magnetized, rotating compact objects. We generalize previous work by including thermal effects and analyze in detail the various forces that guide, accelerate, and collimate the flow. We demonstrate that, under the assumptions of a quasi-steady poloidal magnetic field and of a highly relativistic poloidal velocity, the equations become effectively time independent and the motion can be described as a frozen pulse. We concentrate on trans-Alfvénic solutions and consider outflows that are super-Alfvénic throughout in the companion paper. Our results are applicable to relativistic jets in gamma-ray burst (GRB) sources, active galactic nuclei, and microquasars, but our discussion focuses on GRBs. We envision the outflows in this case to initially consist of a hot and optically thick mixture of baryons, electron-positron pairs, and photons. We show that the flow is at first accelerated thermally but that the bulk of the acceleration is magnetic, with the asymptotic Lorentz factor corresponding to a rough equipartition between the Poynting and kinetic energy fluxes (i.e., ~50% of the injected total energy is converted into baryonic kinetic energy). The electromagnetic forces also strongly collimate the flow, giving rise to an asymptotically cylindrical structure.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/593e6a52ae7e3cdfa61be411ab8310f6afeaf5c4

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

1. Bing Zhang
2. Ramesh Narayan
3. J. McKinney
4. A. Tchekhovskoy
5. Pawan Kumar
6. D. Giannios
7. F. Yuan
8. E. Nakar

In Nuclear and High Energy Physics

1. Ramesh Narayan
2. Bing Zhang
3. J. McKinney
4. A. Tchekhovskoy
5. D. Giannios
6. F. Yuan
7. Y. Lyubarsky
8. Pawan Kumar

Citations in the corpus

• Simulations of ultrarelativistic magnetodynamic jets from gamma‐ray burst engines (2008, background): “…2006), for asymptotic solutions (Appl & Camenzind 1993; Begelman & Li 1994; Lovelace & Romanova 2003; Fendt & Ouyed 2004), or for self-similar solutions that allow variable separation (Contopoulos & Lovelace 1994; Contopoulos 1995; Vlahakis & Königl 2003a,b; Narayan, McKinney & Farmer 2007).”
• The role of kink instability in Poynting-flux dominated jets (2006, background): “Better conversion within ideal MHD appears to be hard to achieve except by decollimation of the flow (Li et al. 1992; Begelman and Li 1994, Bogovalov 2001; Daigne and Drenkhahn 2002; but see claims to the contrary by Vlahakis and Konigl 2003a,b; Fendt and Ouyed 2004).”
• The physics of gamma-ray bursts & relativistic jets (2014, background): “Vlahakis and königl [612], Vlahakis et al.”
• Magnetic acceleration of relativistic AGN jets (2007, background): “…on exact semi-analytic solutions for axisymmetric, highly magnetized, steady outflows under the assumption of radial self-similarity (Li et al. 1992; Vlahakis & K¨onigl 2003a,b, 2004), have demonstrated that magnetic acceleration in non-conical geometries can be quite efficient, typically resulting…”
• Short-hard gamma-ray bursts (2007, background): “…that by the time that the prompt emission is generated, most, or comparable amount, of the energy is in a baryonic component (e.g., Katz 1997; Vlahakis & Königl 2003a,b) while in other models the magnetic field is the dominant component at all times (e.g., Mészáros & Rees 1997b; Lyutikov…”
• Magnetic acceleration of ultrarelativistic jets in gamma-ray burst sources (2008, methodology): “But a closer inspection reveals that the acceleration process exhibits a new mode of behaviour in this case (one that was, however, found before in semi-analytic self-similar solutions; see Vlahakis & Königl 2003b).”
• Are Quasar Jets Dominated by Poynting Flux? (2005, background): “…surfaces (Bernoulli equation) and the crossfield-force balance (Grad-Shafranov equation), and secondly because of the very uncertain boundary conditions at the base of the outflow and along the outermost magnetic surface (Begelman 1998; Heyvaerts & Norman 2003; Vlahakis & Königl 2003a, b).”
• Non-thermal particle acceleration in collisionless relativistic electron-proton reconnection (2016, background): “…is due to the nature of the hydromagnetic acceleration process, which is efficient as long as the jet is magnetically dominated but becomes extremely inefficient once the kinetic energy and Poynting fluxes become comparable (Begelman & Li 1994; Vlahakis & Königl 2003a,b; Komissarov et al. 2007).”
• A Reconnection Switch to Trigger gamma-Ray Burst Jet Dissipation (2010, background): “…are commonly understood to be dynamically important in the jets produced by GRB engines (Narayan, Paczynski & Piran 1992; Thompson 1994; Usov 1994; Vlahakis & Königl 2003; Lyutikov 2006b; Uzdensky & MacFadyen 2006, 2007), only recently have self-consistent MHD simulations been able to model the…”
• ASYMPTOTIC STRUCTURE OF POYNTING-DOMINATED JETS (2009, background): “A few self-similar solutions to the relativistic magnetohydrodynamic (MHD) equations were found (Li et al. 1992; Contopoulos 1995; Vlahakis & Königl 2003a, 2003b; Narayan et al. 2007), which resemble outflows from a disk.”
• Hot Accretion Flows Around Black Holes (2014, background): “…Punsly & Coroniti 1989; Komissarov & McKinney 2007, Tchekhovskoy et al. 2011; Penna et al. 2013a) and the Blandford-Payne model (BP, Blandford & Payne 1982; see also Pudritz & Norman 1983; Heyvaerts & Norman 1989; Li et al. 1992; Contopoulos & Lovelace 1994; Ostriker 1997; Vlahakis & Konigl 2003).”
• THE INTERNAL-COLLISION-INDUCED MAGNETIC RECONNECTION AND TURBULENCE (ICMART) MODEL OF GAMMA-RAY BURSTS (2010, methodology): “The GRB radiation is powered by dissipation of the magnetic field energy in the ejecta (Usov 1992; Thompson 1994; Mészáros and Rees 1997b; Lyutikov and Blandford 2003; Vlahakis and Königl 2003; Lazarian et al. 2003; Lyutikov 2006a).”
• Magnetic Driving of Relativistic Outflows in Active Galactic Nuclei. I. Interpretation of Parsec-Scale Accelerations (2003, background): “Vlahakis & Königl (2003b) derivedanalogous solutions for super-Alfvénic jets, for which the magnetic field at the base of the flow is predominantly azimuthal.”
• EFFICIENCY OF MAGNETIC TO KINETIC ENERGY CONVERSION IN A MONOPOLE MAGNETOSPHERE (2009, background): “1 (Li, Chiueh, & Begelman 1992; Begelman & Li 1994; Vlahakis & Königl 2003a,b; Vlahakis 2004; Beskin & Nokhrina 2006, Barkov & Komissarov 2008; Komissarov et al. 2009).”