COSMIC RAY ACCELERATION AT BLAST WAVES FROM TYPE Ia SUPERNOVAE

By: HYESUNG KANG

Department of Earth Sciences, Pusan National University, Pusan 609 -735, Korea

E-mail: hskang@pusan.ac.kr

(Received November 10, 2006; Accepted December 6, 2006)

ABSTRACT

We have calculated the cosmic ray (CR) acceleration at young remnants from Type Ia supernovae expanding into a uniform interstellar medium (ISM). Adopting quasi-parallel magnetic fields, gasdynamic equations and the diffusion convection equation for the particle distribution function are solved in a comoving spherical grid which expands with the shock. Bohm-type diffusion due to self-excited Alfv´en waves, drift and dissipation of these waves in the precursor and thermal leakage injection were included. With magnetic fields amplified by the CR streaming instability, the particle energy can reach up to 10 16 Z eV at young supernova remnants (SNRs) of several thousand years old. The fraction of the explosion energy transferred to the CR component asymptotes to 40-50 % by that time. For a typical SNR in a warm ISM, the accelerated CR energy spectrum should exhibit a concave curvature with the power-law slope flattening from 2 to 1.6 at E > ∼ 0.1 TeV. Key Words : cosmic ray acceleration – supernova remnants – hydrodynamics – methods:numerical

http://arxiv.org/pdf/astro-ph/0701027.pdf