Cosmic ray acceleration by shock waves interacting with density fluctuations in the interstellar medium
Abstract
There exists a widely spread consensus that galactic cosmic rays (CRs) are produced in supernova remnants in our galaxy and the acceleration mechanism is diffusive shock acceleration (DSA). Although many observations and theories support this picture, there remain some problems such as maximum attainable energies and spectral indices of CR energy spectra. In order to resolve the contradictions between observations and theories, we concentrate on the density fluctuations of the medium in which shock waves propagate and show that sound waves generated by the interaction between shock and fluctuations can accelerate particles via second-order process. This modification is different from major previous studies in that it does not need the nonlinear back-reaction of CR acceleration. In this presentation, we will introduce the theoretical aspect of our study and the results of our Monte Carlo simulations and suggest the possibility to resolve the problems of DSA.
- Publication:
-
43rd COSPAR Scientific Assembly. Held 28 January - 4 February
- Pub Date:
- January 2021
- Bibcode:
- 2021cosp...43E1343Y