Cosmic-ray driven turbulence

Cosmic rays are accelerated at the blast waves sent out into space when a star ends its life in a supernova explosion. But for this process to be effective, the particles must be kept close to the wave for many years. Magnetic fields can do this, but only if they are very strong. Currently, it is thought that strong fields are generated by the cosmic rays themselves, in a kind of bootstrap process. To find out whether or not this can work, we study the plasma instabilities that occur when cosmic rays are accelerated, and make computer simulations of the magnetic turbulence that they drive (see the picture on the title page). Extensive ”particle-in-cell” simulations are needed to determine at what level the turbulence will saturate, which sets the upper limit on the energy to which cosmic rays can be accelerated.

Results of a particle-in-cell simulation showing channels of low density and high magnetic field evacuated by streaming cosmic rays. The colour shading represents (a) the magnetic field strength, and (b) the plasma density.


Recent papers

M. Takamoto, T. Inoue, A. Lazarian, 2015, submitted to ApJ
Turbulent reconnection in relativistic plasmas and effects of compressibility

G. Giacinti, M. Kachelriess, O. Kalashev, A. Neronov, D.V. Semikoz, 2015, Phys. Rev. D.
Unified model for cosmic rays above 10^17 eV and the diffuse gamma-ray and neutrino backgrounds

M. Takamoto, J. G. Kirk, 2015, The Astrophysical Journal
Rapid cosmic-ray acceleration at perpendicular shocks in supernova remnants

Y. Akamatsu, S. Inutsuka, C. Nonaka, M. Takamoto, 2014, Journal of Computational Physics
A new scheme of causal viscous hydrodynamics for relativistic heavy-ion collisions: A Riemann solver for quark-gluon plasma

Reville, Brian & Kirk, John G. 2010, The Astrophysical Journal
Computation of Synthetic Spectra from Simulations of Relativistic Shocks

Reville, B. & Kirk, J. G. 2010, The Astrophysical Journal
Linear Acceleration Emission in Pulsar Magnetospheres

Kirk, John G. & Reville, Brian 2010, The Astrophysical Journal
Radiative Signatures of Relativistic Shocks

O'Sullivan, S., Reville, B., & Taylor, A. M. 2009, Monthly Notices of the Royal Astronomical Society
Stochastic particle acceleration in the lobes of giant radio galaxies

Ohira, Yutaka, Reville, Brian, Kirk, John G., & Takahara, Fumio 2009, The Astrophysical Journal
Two-Dimensional Particle-In-Cell Simulations of the Nonresonant, Cosmic-Ray-Driven Instability in Supernova Remnant Shocks

Reville, B., Kirk, J. G., & Duffy, P. 2009, The Astrophysical Journal
Steady-State Solutions in Nonlinear Diffusive Shock Acceleration