Publications of The Korean Astronomical Society (천문학논총)

The Korean Astronomical Society (한국천문학회)
권호 표지
DOI QR코드

DOI QR Code

PARTICLE ACCELERATION IN SUPERNOVA REMNANTS

  • KANG, HYESUNG (Department of Earth Sciences, Pusan National University)
  • Received : 2014.11.30
  • Accepted : 2015.06.30
  • Published : 2015.09.30
Download PDF
⟨ Previous Next ⟩

Abstract

Most high energy cosmic rays (CRs) are thought to be produced by diffusive shock acceleration (DSA) in supernova remnants (SNRs) within the Galaxy. Plasma and MHD simulations have shown that the self-excitation of MHD waves and amplification of magnetic fields via plasma instabilities are an integral part of DSA for strong collisionless shocks. In this study we explore how plasma processes such as plasma instabilities and wave-particle interactions can affect the energy spectra of CR protons and electrons, using time-dependent DSA simulations of SNR shocks. We demonstrate that the time-dependent evolution of the shock dynamics, the self-amplified magnetic fields and $Alfv{\acute{e}nic$ drift govern the highest energy end of the CR energy spectra. As a result, the spectral cutoffs in nonthermal X-ray and ${\gamma}$-ray radiation spectra are regulated by the evolution of the highest energy particles, which are injected at the early phase of SNRs. We also find that the maximum energy of CR protons can be boosted significantly only if the scale height of the magnetic field precursor is long enough to contain the diffusion lengths of the particles of interests. Thus, detailed understandings of nonlinear wave-particle interactions and time-dependent DSA simulations are crucial for understanding the nonthermal radiation from CR acceleration sources.

Keywords

References

  1. Bell, A. R., 1978, The Acceleration of Cosmic Rays in Shock Fronts. I, MNRAS, 182, 147 https://doi.org/10.1093/mnras/182.2.147
  2. Bell, A. R., 2004, Turbulent Amplification of Magnetic Field and Diffusive Shock Acceleration of Cosmic Rays, MNRAS, 353, 550 https://doi.org/10.1111/j.1365-2966.2004.08097.x
  3. Caprioli, D., 2012, Cosmic-Ray Acceleration in Supernova Remnants: Non-Linear Theory Revised, JCAP, 7, 38
  4. Kang, H., 2010, Cosmic Ray Spectrum in Supernova Remnant Shocks, JKAS, 43, 25
  5. Kang, H., 2012, Diffusive Shock Acceleration with Magnetic Field Amplification and Alfvenic Drift, JKAS, 45, 127
  6. Kang, H., 2013, Effects of Wave-Particle Interactions on Diffusive Shock Acceleration at Supernova Remnants, JKAS, 46, 49
  7. Kang, H. & Jones, T. W., 2006, Numerical Studies of Diffusive Shock Acceleration at Spherical Shocks, APh, 25, 246
  8. Kang, H., Jones, T. W., & Edmon, P. P., 2013, Nonthermal Radiation from Supernova Remnants: Effects of Magnetic Field Amplification and Particle Escape, ApJ, 777, 25 https://doi.org/10.1088/0004-637X/777/1/25
  9. Kang, H., Jones, T. W., & Gieseler, U. D. J., 2002, Numerical Studies of Cosmic-Ray Injection and Acceleration, ApJ, 579, 337 https://doi.org/10.1086/342724
  10. Kang, H., Vahe, P., Ryu, D., & Jones, T. W., 2014, Injection of $\kappa$-like Suprathermal Particles into Diffusive Shock Acceleration, ApJ, 788, 141 https://doi.org/10.1088/0004-637X/788/2/141
  11. Lucek, S. G. & Bell, A. R., 2000, Non-linear Amplification of a Magnetic Field Driven by Cosmic Ray Streaming, MNRAS, 314, 65 https://doi.org/10.1046/j.1365-8711.2000.03363.x
  12. Malkov M. A. & Drury, L.O'C., 2001, Nonlinear Theory of Diffusive Acceleration of Particles by Shock Waves, RPPh, 64, 429
  13. Riquelme, M. A. & Spitkovsky, A., 2009, Nonlinear Study of Bell's Cosmic Ray Current-Driven Instability, ApJ, 694, 626 https://doi.org/10.1088/0004-637X/694/1/626
  14. Skilling, J., 1975, Cosmic Ray Streaming. I - Effect of Alfven Waves on Particles, MNRAS, 172, 557 https://doi.org/10.1093/mnras/172.3.557