Evolution of magnetic fields and cosmic ray acceleration in supernova remnants
Abstract
Observations show that the magnetic field in young supernova remnants (SNRs) is significantly stronger than can be expected from compression of the circumstellar medium (CSM) by a factor four in strong blast waves. Additionally, the polarization is mainly radial, which is also contrary to expected compression of the CSM magnetic field. Cosmic rays (CRs) may help to explain these two observed features. They can increase the compression ratio to factors well over those of regular strong shocks, by adding a relativistic plasma component to the pressure, and by draining the shock of energy when CRs escape from the region. The higher compression ratio will also allow for the contact discontinuity that is subject to the Rayleigh-Taylor (R-T) instability to reach much further out to the forward shock. This could create a preferred radial polarization of the magnetic field. With an adaptive mesh refinement MHD code (AMRVAC), we simulate the evolution of SNRs with three different configurations of the initial CSM magnetic field, and look at two different equations of state in order to look at the possible influence of a CR plasma component. The spectrum of CRs can be simulated using test particles, of which we also show some preliminary results that agree well with available analytical solutions.
- Publication:
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37th COSPAR Scientific Assembly
- Pub Date:
- 2008
- Bibcode:
- 2008cosp...37.2791S
- Keywords:
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- MHD;
- supernova remnants