On 2022 September 5, Parker Solar Probe (Parker) observed a large solar energetic particle (SEP) event at the unprecedented distance of only 15 RS from the Sun. The observations from the Integrated Science Investigation of the Sun (IS⊙IS) obtained over the course of this event are remarkably rich, and an overview is presented here. IS⊙IS is capable of measuring ions from 20 keV to over 100 MeV nuc−1 and electrons from 30 keV to 6 MeV; here, we primarily focus on the proton and helium measurements above 80 keV. Among the surprising results are evidence of inverse velocity dispersion at energies above 1 MeV during the onset of the event, a sharp decrease in the energetic particle intensities at all energies at the interplanetary shock crossing, and repeated short durations of highly anisotropic sunward flow. Many changes in the SEP intensities, anisotropy, and spectral steepness are coincident with solar wind structure boundaries identified using the Parker solar wind magnetic field and plasma data. However, there are significant changes that are not correlated with any clearly visible solar wind variation. The observations presented here serve as an introduction to a complex event with numerous opportunities for future, more in-depth studies.
Published May 10, 2024
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Journal Article
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Observations of the 2022 September 5 Solar Energetic Particle Event at 15 Solar Radii
- Creators
- Cohen, C. M. S.1
- Leske, R. A.1
- Christian, E. R.
- Cummings, A. C.1
- de Nolfo, G. A.
- Desai, M. I.
- Giacalone, J.
- Hill, M. E.
- Labrador, A. W.1
- McComas, D. J.
- McNutt, R. L.
- Mewaldt, R. A.1
- Mitchell, D. G.
- Mitchell, J. G.
- Muro, G. D.1
- Rankin, J. S.
- Schwadron, N. A.
- Sharma, T.
- Shen, M. M.
- Szalay, J. R.
- Wiedenbeck, M. E.
- Xu, Z. G.1
- Romeo, O.
- Vourlidas, A.
- Bale, S. D.
- Pulupa, M.
- Kasper, J. C.
- Larson, D. E.
- Livi, R.
- Whittlesey, P.
Abstract
Copyright and License
© 2024. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
Additional Information
Parker Solar Probe: Insights into the Physics of the Near-Solar Environment
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Cohen_2024_ApJ_966_148.pdf
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Additional details
- ISSN
- 1538-4357
- National Aeronautics and Space Administration
- NNN06AA01C
- National Aeronautics and Space Administration
- 80NSSC22K0970
- Caltech groups
- Space Radiation Laboratory