Magnetic field amplification in nonlinear diffusive shock acceleration including resonant and non-resonant cosmic-ray driven instabilities

Journal Article · Thu Jul 10 04:00:00 EDT 2014 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/789/2/137· OSTI ID:22365673

Bykov, Andrei M.; Osipov, Sergei M. ^[1]; Ellison, Donald C. ^[2]

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1. A. F. Ioffe Physical-Technical Institute, St. Petersburg 194021 (Russian Federation)
2. Department of Physics, North Carolina State University, Raleigh, NC 27695-8202 (United States)

We present a nonlinear Monte Carlo model of efficient diffusive shock acceleration where the magnetic turbulence responsible for particle diffusion is calculated self-consistently from the resonant cosmic-ray (CR) streaming instability, together with non-resonant short- and long-wavelength CR-current-driven instabilities. We include the backpressure from CRs interacting with the strongly amplified magnetic turbulence which decelerates and heats the super-Alfvénic flow in the extended shock precursor. Uniquely, in our plane-parallel, steady-state, multi-scale model, the full range of particles, from thermal (∼eV) injected at the viscous subshock to the escape of the highest energy CRs (∼PeV) from the shock precursor, are calculated consistently with the shock structure, precursor heating, magnetic field amplification, and scattering center drift relative to the background plasma. In addition, we show how the cascade of turbulence to shorter wavelengths influences the total shock compression, the downstream proton temperature, the magnetic fluctuation spectra, and accelerated particle spectra. A parameter survey is included where we vary shock parameters, the mode of magnetic turbulence generation, and turbulence cascading. From our survey results, we obtain scaling relations for the maximum particle momentum and amplified magnetic field as functions of shock speed, ambient density, and shock size.

• OSTI ID: 22365673
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 789; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ACCELERATION
ALFVEN WAVES
AMPLIFICATION
COMPUTERIZED SIMULATION
COSMIC RADIATION
DENSITY
DIFFUSION
FLUCTUATIONS
INSTABILITY
MAGNETIC FIELDS
MAGNETOHYDRODYNAMICS
MONTE CARLO METHOD
PROTON TEMPERATURE
SCALE MODELS
SCATTERING
SHOCK WAVES
SPECTRA
SUPERNOVA REMNANTS
TURBULENCE
VELOCITY