Nonlinear Diffusive Shock Acceleration with Magnetic Field Amplification

By A. Vladimirov, D. Ellison, A. Bykov. 2006

140 citations recorded by the source corpus.

We introduce a Monte Carlo model of nonlinear diffusive shock acceleration that allows for the generation of large-amplitude magnetic turbulence, i.e., ΔB ≫ B0, where B0 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 B0 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.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/caeaaa3d23e57fc7df57169584d7e737b7590f1a

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Nuclear and High Energy Physics

Citations in the corpus

SIMULATIONS OF ION ACCELERATION AT NON-RELATIVISTIC SHOCKS. I. ACCELERATION EFFICIENCY (2013, methodology): “…for a review), via Monte Carlo simulations (e.g., Ellison et al. 1990; Jones & Ellison 1991; Ellison et al. 1995, 1996; Niemiec & Ostrowski 2004; Vladimirov et al. 2006), as well as by solving the CR transport equation either numerically (e.g., Berezhko & Völk 1997, 2004; Kang & Jones 1997;…”
Broad-band non-thermal emission from molecular clouds illuminated by cosmic rays from nearby supernova remnants (2009, background): “The value of pmax depends on a few crucial but poorly known aspects of the problem, including the nature of CR–driven instability operating in the shock precursor and the level of wave damping (Bell and Lucek 2001; Bell 2004; Ptuskin and Zirakashvili 2005; Blasi et al. 2007; Vladimirov et al. 2006).”
Cosmic ray acceleration and escape from supernova remnants (2013, background): “Vladimirov et al (2006) include magnetic field generation in response to gradients in the CR pressure.”
Simulating cosmic rays in clusters of galaxies – II. A unified scheme for radio haloes and relics with predictions of the γ-ray emission (2007, background): “…theoretical understanding of this mechanism is currently an active research topic that includes thermalization processes of the time evolution of the kinetic distribution of particles(Wolfe & Melia 2006) as well as non-linear eff cts and magnetic field amplification (Vladimirov et al. 2006).”
NONTHERMAL RADIATION OF YOUNG SUPERNOVA REMNANTS: THE CASE OF RX J1713.7−3946 (2010, background): “The characteristic diffusive scale of highest energy particles is a small fraction ξ0 1 of the shock radius (see Zirakashvili & Ptuskin 2008) and is determined by the generation and transport of MHD turbulence in the upstream region (see also Vladimirov et al. 2006; Amato & Blasi 2006).”
Observational Signatures of Particle Acceleration in Supernova Remnants (2012, background): “The plasma in the precursor is compressed, heated and accelerated toward the shock speed (Boulares and Cox, 1988; Vladimirov et al., 2008).”