Solar Energetic Proton Access to the Inner Magnetosphere During the September 7–8, 2017 Event

The access of solar energetic protons into the inner magnetosphere on September 7–8, 2017 is investigated by following reversed proton trajectories to compute the proton cutoff energy using the Dartmouth geomagnetic cutoff code (Kress et al., 2010, https://doi.org/10.1029/2009sw000488). The cutoff e...

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Bibliographic Details
Published in:Journal of geophysical research. Space physics 2021-07, Vol.126 (7), p.n/a
Main Authors: Li, Zhao, Engel, Miles, Hudson, Mary, Kress, Brian, Patel, Maulik, Qin, Murong, Selesnick, Richard
Format: Article
Language:English
Subjects:
ASTRONOMY AND ASTROPHYSICS
Charged particles
Driving conditions
Dynamic pressure
Geomagnetic storms
Geomagnetism
Heliospheric and Magnetospheric Physics
Magnetic fields
Magnetic storms
Magnetism
Magnetospheres
Proton flux
Protons
Ring currents
Solar energy
Solar wind
Solar wind dynamics
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Summary:The access of solar energetic protons into the inner magnetosphere on September 7–8, 2017 is investigated by following reversed proton trajectories to compute the proton cutoff energy using the Dartmouth geomagnetic cutoff code (Kress et al., 2010, https://doi.org/10.1029/2009sw000488). The cutoff energies for protons coming from the west and east direction, the minimum and maximum cutoff energy respectively, are calculated every 5 min along the orbit of Van Allen Probes using TS07 and the Lyon‐Fedder‐Mobarry (LFM) MHD magnetic field model. The result shows that the cutoff energy increases significantly as the radial distance decreases, and that the cutoff energy decreases with the building up of the ring current during magnetic storms. Solar wind dynamic pressure also affects cutoff suppression (Kress et al., 2004, https://doi.org/10.1029/2003gl018599). The LFM‐RCM model shows stronger suppression of cutoff energy than TS07 during strong solar wind driving conditions. The simulation result is compared with proton flux measurements, showing consistent variation of the cutoff location during the September 7–8, 2017 geomagnetic storm. Key Points The Dartmouth geomagnetic cutoff code is updated with TS07 and LFM MHD magnetic field snapshots The proton cutoff energy is calculated during the September 7–8, 2017 SEP event Comparison with data shows better correlation using LFM than TS04 and TS07
ISSN:2169-9380
2169-9402
DOI:10.1029/2021JA029107