Long-Term Evolution of Supernova Remnants in Magnetized Interstellar Medium

The evolution of supernova remnants (SNRs) is studied, with particular attention to the effect of magnetic fields with axisymmetric two-dimensional magnetohydrodynamical simulations. The evolution of magnetic SNRs is the same as non-magnetic ones in the adiabatic Sedov stage. After a thin shell is formed, the shell is driven by the pressure of the hot interior gas (bubble). Evolution in the pressure-driven snow-plow phase is much affected by the magnetic field. The shell sweeping the magnetic field lines thickens owing to the magnetic pressure force. After 5 × 10yr 2 × 10yr, the inner boundary of the thick shell begins to contract. This compresses the hot bubble radially and maintains its thermal pressure. Thus, the bubble forms a prolate spheroidal shape and becomes thinner and thinner, since it expands in a direction parallel to the magnetic field for B0 ∼> 3μG. Finally, the bubble contracts. The porosity of the hot low-density gas in ISM is reduced, taking the effect of the magnetic field into account. Subject headings: ISM: bubbles — ISM: magnetic fields — ISM: supernova remnants [email protected] also School of Physical Sciences, The Graduate University for Advanced Studies (SOKENDAI); [email protected]