Particle trajectories and acceleration during 3D fan reconnection

Abstract

Context. The primary energy release in solar flares is almost certainly due to magnetic reconnection, making this a strong candidate as a mechanism for particle acceleration. While particle acceleration in 2D geometries has been widely studied, investigations in 3D are a recent development. Two main classes of reconnection regimes at a 3D magnetic null point have been identified: fan and spine reconnection Aims. Here we investigate particle trajectories and acceleration during reconnection at a 3D null point, using a test particle numerical code, and compare the efficiency of the fan and spine regimes in generating an energetic particle population. Methods. We calculated the time evolution of the energy spectra. We discuss the geometry of particle escape from the two configurations and characterise the trapped and escaped populations. Results. We find that fan reconnection is less efficent than spine reconnection in providing seed particles to the region of strong electric field where acceleration is possible. The establishment of a steady-state spectrum requires approximately double the time in fan reconnection. The steady-state energy spectrum at intermediate energies (protons 1 keV to 0.1 MeV) is comparable in the fan and spine regimes. While in spine reconnection particle escape takes place in two symmetric jets along the spine, in fan reconnection no jets are produced and particles escape in the fan plane, in a ribbon-like structure.

References in corpus (2)

• In situ evidence for the structure of the magnetic null in a 3D reconnection event in the Earth's magnetotail
• Particle Acceleration in three dimensional Reconnection Regions: A New Test Particle Approach

Cited by in corpus (10)

• Recent Advances in Understanding Particle Acceleration Processes in Solar Flares
• Kinetic modeling of particle acceleration in a solar null point reconnection region
• Solar Particle Acceleration at Reconnecting 3D Null Points
• Particle-In-Cell Simulation of Electron Acceleration in Solar Coronal Jets
• Combining MHD and kinetic modelling of solar flares
• Particle acceleration at a reconnecting magnetic separator
• Accelerated particle beams in a 3D simulation of the quiet Sun
• Particle dynamics in a non-flaring solar active region model
• Particle acceleration with anomalous pitch angle scattering in 3D separator reconnection
• Missing bits of the solar jigsaw puzzle: small-scale, kinetic effects in coronal studies