Acceleration of Cosmic Rays at Cosmic Shocks

Details Acceleration of Cosmic Rays at Cosmic Shocks Acceleration of Cosmic Rays at Cosmic Shocks

2003-03-18

arxiv.org/abs/astro-ph/0303404v1

Astronomy and Astrophysics

Astrophysics

12 pages, To appear in Journal of Korean Astronomical Society, March, 2003 issue

Scientific paper

Nonthermal particles can be produced due to incomplete thermalization at collisionless shocks and further accelerated to very high energies via diffusive shock acceleration. In a previous study we explored the cosmic ray (CR) acceleration at cosmic shocks through numerical simulations of CR modified, quasi-parallel shocks in 1D plane-parallel geometry with the physical parameters relevant for the shocks emerging in the large scale structure formation of the universe (Kang & Jones 2002). In order to consider the CR acceleration at shocks with a broader range of physical properties, in this contribution we present additional simulations. For a given Mach number, shocks with higher speeds accelerate CRs faster with a greater number of particles. However, two shocks with a same Mach number but with different shock speeds evolve qualitatively similarly when the results are presented in terms of diffusion length and time scales. Therefore, the time asymptotic value for the fraction of shock kinetic energy transferred to CRs is mainly controlled by shock Mach number rather than shock speed. We present the ``CR energy ratio'' for a wide range of shock parameters and for $\epsilon=0.2-0.3$ at terminal time of our simulations. We suggest that these values can be considered as time-asymptotic values for the CR acceleration efficiency, since the time-dependent evolution of CR modified shocks has become approximately self-similar before the terminal time.

Affiliated with

Also associated with

No associations

Rating

Acceleration of Cosmic Rays at Cosmic Shocks does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Acceleration of Cosmic Rays at Cosmic Shocks, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Acceleration of Cosmic Rays at Cosmic Shocks will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-119046