1 / 24

Сергей Моисеенко , Геннадий Бисноватый-Коган Институт космических исследований , Москва

Моделирование магниторотационных процессов в коллапсирующих сверхновых и развитие Магнито-Дифференциально-Ротационной неустойчивости. Сергей Моисеенко , Геннадий Бисноватый-Коган Институт космических исследований , Москва. Core-collapsed supernovae are brightest events in the Universe. Crab

tmcgee
Télécharger la présentation

Сергей Моисеенко , Геннадий Бисноватый-Коган Институт космических исследований , Москва

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Моделированиемагниторотационных процессов в коллапсирующих сверхновых иразвитие Магнито-Дифференциально-Ротационной неустойчивости Сергей Моисеенко, Геннадий Бисноватый-Коган Институт космических исследований, Москва

  2. Core-collapsed supernovae are brightest events in the Universe. Crab nebula Cas A SN1987A

  3. Magnetorotational mechanism for the supernova explosion was suggested by Bisnovatyi-Kogan (1970) Amplification of magnetic fields due to differential rotation, angular momentum transfer by magnetic field. Part of the rotational energy is transformed to the energy of explosion

  4. Basic equations: MHD +self-gravitation, infinite conductivity: Additional condition divH=0 Axis symmetry ( )and equatorial symmetry (z=0) are supposed. Notations:

  5. Magnetorotational supernova in 1D Bisnovaty-Kogan et al. 1976, Ardeljan et al. 1979 Example:

  6. (Thanks to E.A.Skiba) (Thanks to E.A.Skiba)

  7. Presupernova Core Collapse Equations of state take into account degeneracy of electrons and neutrons, relativity for the electrons, nuclear transitions and nuclear interactions. Temperature effects were taken into account approximately by the addition of radiation pressure and an ideal gas . Neutrino losses were taken into account in the energy equations. A cool white dwarf was considered at the stability limit with a mass equal to the Chandrasekhar limit. To obtain the collapse we increase the density at each point by 20% and we also impart uniform rotation on it.

  8. Operator-difference scheme (finite volumes) Ardeljan & Kosmachevskii Comp. and Math. Modeling 1995, 6, 209 and references therein Lagrangian, implicit, triangular grid with rezoning, completely conservative Method of basic operators (Samarskii) – grid analogs of basic differential operators: GRAD(scalar) (differential) ~ GRAD(scalar) (grid analog) DIV(vector) (differential) ~ DIV(vector) (grid analog) CURL(vector) (differential) ~ CURL(vector) (grid analog) GRAD(vector) (differential) ~ GRAD(vector) (grid analog) DIV(tensor) (differential) ~ DIV(tensor) (grid analog) Implicit scheme. Time step restrictions are weaker for implicit schemes (no CFL condition). The scheme is Lagrangian=> conservation of angular momentum.

  9. Operator-difference scheme for hydro equations where

  10. Example of calculation with the triangular grid

  11. Initial magnetic field –quadrupole-and dipole-like symmetries

  12. Magnetorotational explosion for the quadruppole-like magnetic field Temperature and velocity field Specific angular momentum

  13. Magnetorotational explosion for the dipole-like magnetic field

  14. Time evolution of different types of energies

  15. Ejected energy and mass Ejected energy Ejected mass 0.14M Particle is considered “ejected” – if its kinetic energy is greater than its potential energy

  16. Magnetorotational explosion for the different Magnetorotational instability mag. field grows exponentially (Dungey 1958,Velikhov 1959, Chandrasekhar1970,Tayler 1973, Balbus & Hawley 1991, Spruit 2002, Akiyama et al. 2003…)

  17. Dependence of the explosion time from (for small ) Example:

  18. MRI in 2D – Tayler instability Tayler, R. MNRAS 1973

  19. Toy model for MDRI in the magnetorotational supernova at the initial stage of the process beginning of the MRI => formation of multiplepoloidaldifferentially rotating vortexes in general we may approximate: Assuming for the simplicity that is a constant during the first stages of MRI, and taking as a constant we come to the following equation:

  20. No MDRI MDRI B_0=10(9)G B_0=10(12)G

  21. MDRI development Toroidal to poloidal magnetic energy relation

  22. 3D simulations Mikami H., Sato Y., Matsumoto T.,Hanawa, T. ApJ 2008, 683, 357 ( no neutrino) recently P.Mosta et al. MR supernovae in 3D ApJL 2014, 785, L29 Authors observe no runaway explosion by the end of the full 3D simulation at 185 ms after bounce. Detailed 3D MR supernova simulations are necessary.

  23. 3D thetrahedral grid 3D – work in progress

  24. Conclusions • Magnetorotational mechanism (MRM) produces enough energy for the core collapse supernova. • The MRM is weakly sensitive to the neutrino cooling mechanism and details of the EoS. • MR supernova shape depends on the configuration of the magnetic field and is always asymmetrical. • MRDI is developed in MR supernova explosion.

More Related