Special relativistic magnetohydrodynamic simulation of two-component outflow powered by magnetic explosion on compact stars

Jin Matsumoto, Youhei Masada, Eiji Asano, Kazunari Shibata

Research output: Chapter in Book/Report/Conference proceedingConference contribution


The nonlinear dynamics of the outflow driven by magnetic explosion on the surface of compact object is investigated through special relativistic magnetohydrodynamic simulations. We adopt, as an initial equilibrium state, a spherical stellar object embedded in the hydrostatic plasma which has a density ρ(r) α r-alpha; and is threaded by a dipole magnetic field. The injection of magnetic energy at the surface of compact star breaks the dynamical equilibrium and triggers two-component outflow. At the early evolutionary stage, the magnetic pressure increases rapidly in time around the stellar surface, initiating a magnetically driven outflow. Then it excites a strong forward shock, shock driven outflow. The expansion velocity of the magnetically driven outflow is characterized by the Alfvén velocity on the stellar surface, and follows a simple scaling relation νmag α νA1/2. When the initial density profile declines steeply with radius, the strong shock is accelerated self-similarly to relativistic velocity ahead of the magnetically driven component. We find that the evolution of the strong forward shock can be described by a self-similar relation Γsh α rsh, where Γsh is the Lorentz factor of the plasma measured at the shock surface rsh. It should be stressed that the pure hydrodynamic process is responsible for the acceleration of the shock driven outflow. Our two-component outflow model, which is the natural outcome of the magnetic explosion, would deepen the understanding of the magnetic active phenomena on various magnetized stellar objects.

Original languageEnglish
Title of host publicationAdvances in Plasma Astrophysics
EditorsAlfio Bonanno, Elisabete de Gouveia Dal Pino, Alexander Kosovichev
Number of pages4
Publication statusPublished - 2010 Sept
Externally publishedYes

Publication series

NameProceedings of the International Astronomical Union
ISSN (Print)1743-9213
ISSN (Electronic)1743-9221


  • MHD
  • neutron stars
  • numerical
  • relativistic

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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