Estimation of the release time of solar energetic particles near the Sun

Abstract

This paper investigates the onset time of Solar Energetic Particle (SEP) events with numerical simulations, and analyses the accuracy of the Velocity Dispersion Analysis (VDA) method. Using a 3-dimensional focused transport model, we calculate the fluxes of protons observed in the ecliptic at 1 AU in the energy range between 10 MeV and 80 MeV. In particular, three models are used to describe different SEP sources produced by flare or coronal shock, and the effects of particle perpendicular diffusion in the interplanetary space are also studied. We have the following findings: When the observer is disconnected from the source, the effects of perpendicular diffusion in the interplanetary space and particles propagating in the solar atmosphere have significant influence on the VDA results. As a result, although the VDA method is valid with impulsive source duration, low background, and weak scattering in the interplanetary space or fast diffusion in the solar atmosphere, the method is not valid with gradual source duration, high background, or strong scattering.

Accepted by ApJ

References in corpus (3)

• Electron and proton acceleration during the first ground level enhancement of solar cycle 24
• The Modification of the Nonlinear Guiding Center Theory
• A numerical simulation of solar energetic particle dropouts during impulsive events

Cited by in corpus (11)

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• A Primer on Focused Solar Energetic Particle Transport: Basic physics and recent modelling results
• Statistical analysis of interplanetary magnetic field path lengths from solar energetic electron events observed by WIND
• Investigation of the possible source for solar energetic particle event of 2017 September 10
• An analytical model of turbulence in Parker spiral geometry and associated magnetic field line lengths
• Large solar energetic particle event that occurred on 2012 March 7 and its VDA analysis
• On the Pulse Shape of Ground Level Enhancements
• Three-stage Acceleration of Solar Energetic Particles Detected by Parker Solar Probe
• Parker Solar Probe observations of solar energetic particle (SEP) events with inverse velocity arrival (IVA) features