Multi-spacecraft observations and transport simulations of solar energetic particles for the May 17th 2012 event

Abstract

The injection, propagation and arrival of solar energetic particles (SEPs) during eruptive solar events is an important and current research topic of heliospheric physics. During the largest solar events, particles may have energies up to a few GeVs and sometimes even trigger ground-level enhancements (GLEs) at Earth. We study the first GLE-event of solar cycle 24, from 17th May 2012, using data from multiple spacecraft (SOHO, GOES, MSL, STEREO-A, STEREO-B and MESSENGER). These spacecraft are located throughout the inner heliosphere, at heliocentric distances between 0.34 and 1.5 astronomical units (au), covering nearly the whole range of heliospheric longitudes. We present and investigate sub-GeV proton time profiles for the event at several energy channels, obtained via different instruments aboard the above spacecraft. We investigate issues due to magnetic connectivity, and present results of three-dimensional SEP propagation simulations. We gather virtual time profiles and perform qualitative and quantitative comparisons with observations, assessing longitudinal injection and transport effects as well as peak intensities. We distinguish different time profile shapes for well-connected and weakly connected observers, and find our onset time analysis to agree with this distinction. At select observers, we identify an additional low-energy component of Energetic Storm Particles (ESPs). Using well-connected observers for normalisation, our simulations are able to accurately recreate both time profile shapes and peak intensities at multiple observer locations. This synergetic approach combining numerical modeling with multi-spacecraft observations is crucial for understanding the propagation of SEPs within the interplanetary magnetic field. Our novel analysis provides valuable proof of the ability to simulate SEP propagation throughout the inner heliosphere, at a wide range of longitudes.

arXiv comment12 pages, 8 figures, 1 table. Accepted for publication in Astronomy & Astrophysics

References in corpus (17)

• PAMELA - A Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics
• Properties of Ground Level Enhancement Events and the Associated Solar Eruptions during Solar Cycle 23
• The First Ground Level Enhancement Event of Solar Cycle 24: Direct Observation of Shock Formation and Particle Release Heights
• Deriving the properties of coronal pressure fronts in 3-D: application to the 17 May 2012 ground level enhancement
• Solar energetic particle access to distant longitudes through turbulent field-line meandering
• What Are Special About Ground-Level Events? Flares, CMEs, Active Regions And Magnetic Field Connection
• Drift-induced perpendicular transport of Solar Energetic Particles
• Electron and proton acceleration during the first ground level enhancement of solar cycle 24
• Energetic particle cross-field propagation early in a solar event
• Analysis of Ground Level Enhancements (GLE): Extreme solar energetic particle events have hard spectra
• Modelling of proton acceleration in application to a ground level enhancement
• PAMELA's Measurements of Magnetospheric Effects on High Energy Solar Particles
• Solar Energetic Particle Events with Protons above 500 MeV between 1995 and 2015 Measured with SOHO/EPHIN
• Modelling Solar Energetic Particle transport near a wavy Heliospheric Current Sheet
• Solar Energetic Particle transport near a Heliospheric Current Sheet
• Drift-induced deceleration of Solar Energetic Particles
• Early propagation of energetic particles across the mean field in turbulent plasmas

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• A Primer on Focused Solar Energetic Particle Transport: Basic physics and recent modelling results
• 3D propagation of relativistic solar protons through interplanetary space
• Modelling the transport of relativistic solar protons along a heliospheric current sheet during historic GLE events
• On the Turbulent Reduction of Drifts for Solar Energetic Particles