The Acceleration of High-energy Protons at Coronal Shocks: The Effect of Large-scale Streamer-like Magnetic Field Structures

Xiangliang Kong, Fan Guo, Joe Giacalone, Hui Li, Yao Chen

Research output: Contribution to journalArticle

8 Scopus citations

Abstract

Recent observations have shown that coronal shocks driven by coronal mass ejections can develop and accelerate particles within several solar radii in large solar energetic particle (SEP) events. Motivated by this, we present an SEP acceleration study that including the process in which a fast shock propagates through a streamer-like magnetic field with both closed and open field lines in the low corona region. The acceleration of protons is modeled by numerically solving the Parker transport equation with spatial diffusion both along and across the magnetic field. We show that particles can be sufficiently accelerated to up to several hundred MeV within 2-3 solar radii. When the shock propagates through a streamer-like magnetic field, particles are more efficiently accelerated compared to the case with a simple radial magnetic field, mainly due to perpendicular shock geometry and the natural trapping effect of closed magnetic fields. Our results suggest that the coronal magnetic field configuration is an important factor for producing large SEP events. We further show that the coronal magnetic field configuration strongly influences the distribution of energetic particles, leading to different locations of source regions along the shock front where most high-energy particles are concentrated. This work may have strong implications for SEP observations. The upcoming Parker Solar Probe will provide in situ observations for the distribution of energetic particles in the coronal shock region, and test the results of the study.

Original languageEnglish (US)
Article number38
JournalAstrophysical Journal
Volume851
Issue number1
DOIs
StatePublished - Dec 10 2017

Keywords

  • Sun: corona
  • Sun: coronal mass ejections (CMEs)
  • Sun: magnetic fields
  • Sun: particle emission
  • acceleration of particles
  • shock waves

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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