Supernovae, Magnetic Fields, and Magnetars: Dynamical Interaction of a Magnetic Bubble with the Interstellar Medium
Last year, Kouveliotou et al. (1998) discovered a new class of short-lived old stellar objects known as magnetars. When a massive star undergoes the catastrophic collapse which precedes a supernova explosion, it undergoes a very rapid spin-up causing its attached dipolar magnetic field lines to become very tightly wound in a toroidal configuration achieving strengths of 10(15) Gauss or more. The corresponding Larmor radius is very small in contrast with the collisional mean free path, and a magnetically-driven collisionless shock of a beta =0 plasma (i.e., magnetic pressure much stronger than the thermal pressure) proceeds into the surrounding interstellar medium. In this paper, we explore the dynamical evolution of this magnetically-driven shock and its scaling properties. In addition, we explore the transition from an MHD-driven shock to a gas dynamical shock (the Sedov solution), as Ohmic dissipation ultimately converts the energy contained in the magnetic field into thermal energy.
AAS/Division of Dynamical Astronomy Meeting
- Pub Date:
- September 1999