Turbulence Dissipation and Particle Injection in Nonlinear Diffusive Shock Acceleration with Magnetic Field Amplification
- 1 December 2008
- journal article
- Published by American Astronomical Society in The Astrophysical Journal
- Vol. 688 (2), 1084-1101
- https://doi.org/10.1086/592240
Abstract
The highly amplified magnetic fields suggested by observations of some supernova remnant shells are most likely an intrinsic part of efficient particle acceleration by shocks. This strong turbulence, which may result from cosmic- ray-driven instabilities, both resonant and nonresonant, in the shock precursor, is certain to play a critical role in self- consistent, nonlinear models of strong, cosmic-ray-modified shocks. Here we present a Monte Carlo model of nonlineardiffusiveshockacceleration(DSA) accountingfor magneticfieldamplificationthroughresonantinstabilities induced by accelerated particles, and including the effects of dissipation of turbulence upstream of a shock and the subsequent precursor plasma heating. Feedback effects between the plasma heating due to turbulence dissipation and particle injection are strong, adding to the nonlinear nature of efficient DSA. Describing the turbulence damping in a parameterized way, we reach two important results: first, for conditions typical of supernova remnant shocks, even a small amount of dissipated turbulence energy (� 10%) is sufficient to significantly heat the precursor plasma; and second,theheatingupstreamof theshockleadstoanincreaseintheinjectionof thermalparticlesatthesubshockbya factor of several. In our results, the response of the nonlinear shock structure to the boost in particle injection pre- vented the efficiency of particle acceleration and magnetic field amplification from increasing. We argue, however, that more advanced(possiblynonresonant) modelsof turbulence generation and dissipation mayleadto ascenarioin which particle injection boost due to turbulence dissipation results in more efficient acceleration and even stronger amplified magnetic fields than without the dissipation. Subject headinggs: acceleration of particles — cosmic rays — magnetic fields — shock waves — supernova remnants — turbulenceKeywords
Other Versions
This publication has 38 references indexed in Scilit:
- Non-linear particle acceleration at non-relativistic shock waves in the presence of self-generated turbulenceMonthly Notices of the Royal Astronomical Society, 2006
- Turbulent amplification of magnetic field and diffusive shock acceleration of cosmic raysMonthly Notices of the Royal Astronomical Society, 2004
- Confirmation of strong magnetic field amplification and nuclear cosmic ray acceleration in SN 1006Astronomy & Astrophysics, 2003
- Small‐Scale Structure of the SN 1006 Shock withChandraObservationsThe Astrophysical Journal, 2003
- Cosmic ray acceleration to very high energy through the non-linear amplification by cosmic rays of the seed magnetic fieldMonthly Notices of the Royal Astronomical Society, 2001
- A Simple Model of Nonlinear Diffusive Shock AccelerationThe Astrophysical Journal, 1999
- Acceleration of Solar Wind Ions by Nearby Interplanetary Shocks: Comparison of Monte Carlo Simulations withUlyssesObservationsThe Astrophysical Journal, 1997
- Particle acceleration at astrophysical shocks: A theory of cosmic ray originPhysics Reports, 1987
- Transmission and damping of hydromagnetic waves behind a strong shock front: implications for cosmic ray accelerationMonthly Notices of the Royal Astronomical Society, 1986
- The acceleration of cosmic rays in shock fronts - IMonthly Notices of the Royal Astronomical Society, 1978