Particle Acceleration in Two Converging Shocks

Xin Wang, Joe Giacalone, Yihua Yan, Mingde Ding, Na Wang, Hao Shan

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

Observations by spacecraft such as ACE, STEREO, and others show that there are proton spectral "breaks" with energy E br at 1-10 MeV in some large CME-driven shocks. Generally, a single shock with the diffusive acceleration mechanism would not predict the "broken" energy spectrum. The present paper focuses on two converging shocks to identify this energy spectral feature. In this case, the converging shocks comprise one forward CME-driven shock on 2006 December 13 and another backward Earth bow shock. We simulate the detailed particle acceleration processes in the region of the converging shocks using the Monte Carlo method. As a result, we not only obtain an extended energy spectrum with an energy "tail" up to a few 10 MeV higher than that in previous single shock model, but also we find an energy spectral "break" occurring on ∼5.5 MeV. The predicted energy spectral shape is consistent with observations from multiple spacecraft. The spectral "break," then, in this case is caused by the interaction between the CME shock and Earth's bow shock, and otherwise would not be present if Earth were not in the path of the CME.

Original languageEnglish (US)
Article number74
JournalAstrophysical Journal
Volume842
Issue number2
DOIs
StatePublished - Jun 20 2017

Keywords

  • Sun: coronal mass ejections (CMEs)
  • acceleration of particles
  • methods: numerical
  • scattering
  • shock waves
  • turbulence

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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