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| Paper: |
Cosmic Ray Spectrum in Supernova Remnant Shocks |
| Volume: |
444, 5th International Conference of Numerical Modeling of Space Plasma Flows (ASTRONUM 2010) |
| Page: |
28 |
| Authors: |
Kang, H. |
| Abstract: |
We performed kinetic simulations of diffusive shock acceleration
in Type Ia supernova remnants (SNRs) expanding into a uniform
interstellar medium (ISM).
The preshock gas temperature is the primary parameter that governs
the cosmic ray (CR) acceleration,
while magnetic field strength and CR injection rate are secondary parameters.
SNRs in the hot ISM, with an injection fraction smaller than 10–4,
are inefficient accelerators with less than 10 % energy getting converted
to CRs. The shock structure is almost test-particle like and the
ensuing CR spectrum can be steeper than E–2.
Although the particles can be accelerated to the knee energy of 1015.5ZeV
with amplified magnetic fields in the precursor,
Alfvénic drift of scattering centers softens the source spectrum as steep
as E–2.1 and reduces the CR acceleration efficiency. |
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