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Maxim Barkov MPI-K, Heidelberg, Germany Space Research Institute, Russia, University of Leeds, UK

Accretion/Blandford-Znajeck processes and jet formation. Maxim Barkov MPI-K, Heidelberg, Germany Space Research Institute, Russia, University of Leeds, UK Serguei Komissarov University of Leeds, UK. Blandford-Znajek mechanism.

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Maxim Barkov MPI-K, Heidelberg, Germany Space Research Institute, Russia, University of Leeds, UK

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  1. Accretion/Blandford-Znajeck processes and jet formation Maxim Barkov MPI-K, Heidelberg, Germany Space Research Institute, Russia, University of Leeds, UK Serguei Komissarov University of Leeds, UK Variable Galactic Gamma-Ray Sources , Heidelberg, Germany

  2. Blandford-Znajek mechanism In the last few years we can see significant progress in general relativistic magneto hydrodynamics (GRMHD) simulations of BH accretion systems. It reveals a flow structure that can be decomposed into a disk, corona, disk wind and highly magnetized polar region that contains the jet (De Villiers, Hawley and Krolik 2003; Hawley and Krolik 2006; McKinney and Gammie 2004; McKinney 2005, 2006, 2007; McKinney and Balndford 2009; Shibata, Sekiguchi and Takahashi, 2007, Barkov and Komissarov 2008, 2010, Barkov and Baushev 2011). Variable Galactic Gamma-Ray Sources , Heidelberg, Germany

  3. Variable Galactic Gamma-Ray Sources , Heidelberg, Germany

  4. III. Numerical simulations Setup (Barkov & Komissarov 2008a,b) (Komissarov & Barkov 2009) Uniform magnetization R=4500km Y= 4x1027-4x1028Gcm-2 black hole M=3Msun a=0.9 Rotation: rc=6.3x103km l0 = 1017 cm2 s-1 • 2D axisymmetric • GRMHD; • Kerr-Schild metric; • Realistic EOS; • Neutrino cooling; • Starts at 1s from • collapse onset. • Lasts for < 1s outer boundary, R= 2.5x104 km free fall accretion (Bethe 1990) Variable Galactic Gamma-Ray Sources , Heidelberg, Germany

  5. Free fall model of collapsing star(Bethe, 1990)‏ radial velocity: mass density: accretion rate: Gravity: gravitational field of Black Hole only (Kerr metric); no self-gravity; Microphysics: neutrino cooling ; realistic equation of state, (HELM, Timmes & Swesty, 2000); dissociation of nuclei (Ardeljan et al., 2005); Ideal Relativistic MHD - no physical resistivity (only numerical); Variable Galactic Gamma-Ray Sources , Heidelberg, Germany

  6. Model:A C1=9; Bp=3x1010 G unit length=4.5km t=0.24s log10 B/Bp log10  (g/cm3) log10 P/Pm magnetic field lines, and velocity vectors Variable Galactic Gamma-Ray Sources , Heidelberg, Germany

  7. Model:A C1=9; Bp=3x1010 G unit length=4.5km t=0.31s log10  (g/cm3) magnetic field lines, and velocity vectors Variable Galactic Gamma-Ray Sources , Heidelberg, Germany

  8. Model:A C1=9; Bp=3x1010 G log10  (g/cm3) magnetic field lines Variable Galactic Gamma-Ray Sources , Heidelberg, Germany

  9. Model:C C1=3; Bp=1010 G log10 P/Pm velocity vectors Variable Galactic Gamma-Ray Sources , Heidelberg, Germany

  10. Jets are powered mainly by the black hole via the Blandford-Znajek mechanism !! Model: C • No explosion if a=0; • Jets originate from the black hole; • ~90% of total magnetic flux is accumulated by the black hole; • Energy flux in the ouflow ~ energy flux through the horizon (disk contribution < 10%); • Theoretical BZ power: Variable Galactic Gamma-Ray Sources , Heidelberg, Germany

  11. 1/50 of case a=0.9 Variable Galactic Gamma-Ray Sources , Heidelberg, Germany

  12. Variable Galactic Gamma-Ray Sources , Heidelberg, Germany

  13. Variable Galactic Gamma-Ray Sources , Heidelberg, Germany

  14. Different magnetic field topologies: Dipole, quadruple 1 and quadruple 2. The initial conditions consist of an equilibrium torus (Fishbone and Moncrief 976; Abramowicz et al. 1978; Komissarov 2006), which is a "torus" of plasma with a black hole at the center. The value of the specific angular momentum of matter and angular momentum of BH ‘a’ determines the total effective potential. Variable Galactic Gamma-Ray Sources , Heidelberg, Germany

  15. Magnetic flux Ψ time evolution Time evolution of magnetic flux of Dipole model on radius r=4.7 rgleft panel and on horizon central panel, t=0.00496 sec -- solid, t=0.0248 sec -- dashed, t=0.0495 sec -- dot dashed, t=0.0991 sec -- doted, t=0.346 sec -- three dots dashed. Time evolution of magnetic flux of model Quadruple 2 on horizon, t=0.00496 sec -- solid, t=0.0248 sec -- dashed, t=0.1238 sec -- doted, t=0.4452 sec -- three dots dashed. Variable Galactic Gamma-Ray Sources , Heidelberg, Germany

  16. Dipole Quadruple 1 Quadruple 2 Radial component of magnetic field. Variable Galactic Gamma-Ray Sources , Heidelberg, Germany

  17. Quadruple 2. Radial component of magnetic field. Variable Galactic Gamma-Ray Sources , Heidelberg, Germany

  18. Flux of matter (MA) - bottom panels and electromagnetic (EM) - up panels per radian depends on θ and time on radius R=180 rg. a=0 a=0.9 In our simulations up to ½ of initial electromagnetic flux are transformed to non-relativistic hot wind though numerous shock waves. It can supply hot corona in such objects as SS433. Variable Galactic Gamma-Ray Sources , Heidelberg, Germany

  19. Lorentz factor • Distribution of Lorentz factor and magnetic lines for time 0.2075 sec. • Cooling case provides most stable and powerful outflow. • The Lorentz factor achieves Γ≤ 4.5 (numerical restriction) No cooling Modified cooling Cooling Variable Galactic Gamma-Ray Sources , Heidelberg, Germany

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