Nils Schween (Germany)
nils.schween @ mpi-hd.mpg.de
Particle acceleration at supernova remnant shocks
Galactic cosmic rays (CRs) are believed to be primarily accelerated in supernova remnant (SNR) shocks. The standard diffusive shock acceleration theory (DSA) predicts for the accelerated particles’ energy spectrum a power law with exponent -2 in the strong shock limit. If compared to the observed spectrum of particles arriving at the earth, a deviation from the theoretical prediction has to be noted. The supernovae should thus release softer spectra into the interstellar medium (ISM) . This deviation may be due to the restriction to parallel shocks in standard DSA. Bell et al. (2011) revisited the problem of DSA with arbitrary field orientation and found that a significant deviation from the standard result is possible, even in the test particle limit. The results for exactly perpendicular shocks were confirmed by Takamoto & Kirk (2015) also in the test particle limit. However, since CR acceleration in SNRs must be efficient, the non-linear feedback of the accelerated particles on the fluid should be taken into account.
We propose to numerically study the system of magnetohydrodynamic equations (MHD) coupled with a kinetic prescription for the self-consistent evolution of the accelerating particles. The results of our investigations will be applied to known high-energy gamma-ray sources such as the TeV supernova RX J1713.7-3946, and other Galactic sources. The effects of additional physical processes, and their potential radiative signatures will be explored.
Supervisor: Brian Reville (MPIK)