Electron Acceleration at a Coronal Shock Propagating Through a Large-scale Streamer-like Magnetic Field

Abstract

With a test-particle simulation, we investigate the effect of large-scale coronal magnetic fields on electron acceleration at an outward-propagating coronal shock with a circular front. The coronal field is approximated by an analytical solution with a streamer-like magnetic field featured by partially open magnetic field and a current sheet at the equator atop the closed region. We show that the large-scale shock-field configuration, especially the relative curvature of the shock and the magnetic field line across which the shock is sweeping, plays an important role in the efficiency of electron acceleration. At low shock altitudes, when the shock curvature is larger than that of magnetic field lines, the electrons are mainly accelerated at the shock flanks; at higher altitudes, when the shock curvature is smaller, the electrons are mainly accelerated at the shock nose around the top of closed field lines. The above process reveals the shift of efficient electron acceleration region along the shock front during its propagation. It is also found that in general the electron acceleration at the shock flank is not so efficient as that at the top of closed field since at the top a collapsing magnetic trap can be formed. In addition, we find that the energy spectra of electrons is power-law like, first hardening then softening with the spectral index varying in a range of -3 to -6. Physical interpretations of the results and implications on the study of solar radio bursts are discussed.

accepted by ApJ

References in corpus (22)

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Cited by in corpus (12)

• The Acceleration and Confinement of Energetic Electrons by a Termination Shock in a Magnetic Trap: An Explanation for Nonthermal Loop-top Sources during Solar Flares
• The acceleration of high-energy protons at coronal shocks: the effect of large-scale streamer-like magnetic field structures
• Multiple injections of energetic electrons associated with the flare/CME event on 9 October 2021
• The Acceleration of Energetic Particles at Coronal Shocks and Emergence of a Double Power Law Feature in Particle Energy Spectra
• Dynamical modulation of solar flare electron acceleration due to plasmoid-shock interactions in the looptop region
• Investigation of the possible source for solar energetic particle event of 2017 September 10
• Observation of a Metric Type N Solar Radio Burst
• Double-power-law feature of energetic particles accelerated at coronal shocks
• An imaging study of a complex solar coronal radio eruption
• The Broken Lane of a Type II Radio Burst Caused by Collision of a Coronal Shock with a Flare Current Sheet
• Corrugated Features in Coronal-mass-ejections-driven Shocks: A Discussion on the Predisposition to Particle Acceleration
• Imaging Preflare Broadband Pulsations in the Decimetric-metric Wavelengths