2006/06/30 by Andrey Vladimirov, Donald C. Ellison, A. M. Bykov +1 · 9 citations
Physics and Astronomy · #Acceleration #Astrophysics #Astrophysics and Cosmic Phenomena #Classical mechanics #Computational physics #Cosmic ray #Field (mathematics) #Gamma-ray bursts and supernovae #Mach number #Magnetic field #Mechanics #Momentum (technical analysis) #Nonlinear system #Particle acceleration #Physics #Quantum electrodynamics #Quantum mechanics #Shock (circulatory) #Shock wave #Solar and Space Plasma Dynamics #Turbulence #astro-ph
paper · pdf · doi:10.1086/508154
published as Astrophys.J.652:1246-1258,2006 · Accepted in ApJ July 2006, typos corrected in this version
arxiv created 2006/08/01 · openalex publication_date 2006/11/27 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We introduce a Monte Carlo model of nonlinear diffusive shock acceleration that allows for the generation of large-amplitude magnetic turbulence, i.e., Δ B ≫ B 0 , where B 0 is the ambient magnetic field. The model is the first to include strong wave generation, efficient particle acceleration to relativistic energies in nonrelativistic shocks, and thermal particle injection in an internally self-consistent manner. We find that the upstream magnetic field B 0 can be amplified by large factors and show that this amplification depends strongly on the ambient Alfvén Mach number. We also show that, in the nonlinear model, large increases in B do not necessarily translate into a large increase in the maximum particle momentum a particular shock can produce, a consequence of high-momentum particles diffusing in the shock precursor where the large amplified field converges to the low ambient value. To deal with the field growth rate in the regime of strong fluctuations, we extend to strong turbulence a parameterization that is consistent with the resonant quasi-linear growth rate in the weak turbulence limit. We believe our parameterization spans the maximum and minimum range of the fluctuation growth, and within these limits we show that the nonlinear shock structure, acceleration efficiency, and thermal particle injection rates depend strongly on the yet to be determined details of wave growth in strongly turbulent fields. The most direct application of our results will be to estimate magnetic fields amplified by strong cosmic-ray modified shocks in supernova remnants.