2001/04/03 by Pasquale Blasi · 153 citations
Physics and Astronomy · #Acceleration #Astrophysics #Astrophysics and Cosmic Phenomena #Classical mechanics #Fermi Gamma-ray Space Telescope #Fermi acceleration #Gamma-ray bursts and supernovae #Jump #Mechanics #Particle (ecology) #Particle acceleration #Physics #Quantum mechanics #Shock (circulatory) #Shock wave #Simple (philosophy) #Solar and Space Plasma Dynamics #Statistical physics #astro-ph
paper · pdf · doi:10.1016/s0927-6505(01)00127-x
published in Astroparticle Physics 16(4), 429-439 (Elsevier BV) · 20 pages, 9 figures. To appear in Astroparticle Physics
arxiv created 2001/04/03 · openalex publication_date 2002/02/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Shocks in astrophysical fluids can generate suprathermal particles by first order (or diffusive) Fermi acceleration. In the test particle regime there is a simple relation between the spectrum of the accelerated particles and the jump conditions at the shock. This simple picture becomes complicated when the pressure of the accelerated particles becomes comparable with the pressure of the shocked fluid, so that the non-linear backreaction of the particles becomes non negligible and the spectrum is affected in a substantial way. Though only numerical simulations can provide a fully self-consistent approach, a more direct and easily applicable method would be very useful, and would allow to take into account the non-linear effects in particle acceleration in those cases in which they are important and still neglected. We present here a simple semi-analytical model that deals with these non-linear effects in a quantitative way. This new method, while compatible with the previous simplified results, also provides a satisfactory description of the results of numerical simulations of shock acceleration.