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Energetic particle evolution during coronal mass ejection passage from 0.3 to 1 AU

Joyce, C. J. and McComas, D. J. and Schwadron, N. A. and Vourlidas, A. and Christian, E. R. and McNutt, R. L. and Cohen, C. M. S. and Leske, R. A. and Mewaldt, R. A. and Stone, E. C. and Mitchell, D. G. and Hill, M. E. and Roelof, E. C. and Allen, R. C. and Szalay, J. R. and Rankin, J. S. and Desai, M. I. and Giacalone, J. and Matthaeus, W. H. and Niehof, J. T. and de Wet, W. and Winslow, R. M. and Bale, S. D. and Kasper, J. C. (2021) Energetic particle evolution during coronal mass ejection passage from 0.3 to 1 AU. Astronomy and Astrophysics, 651 . Art. No. A2. ISSN 0004-6361. doi:10.1051/0004-6361/202039933.

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We provide analysis of a coronal mass ejection (CME) that passed over Parker Solar Probe (PSP) on January 20, 2020 when the spacecraft was at just 0.32 AU. The Integrated Science Investigation of the Sun instrument suite measures energetic particle populations associated with the CME before, during, and after its passage over the spacecraft. We observe a complex evolution of energetic particles, including a brief ~2 h period where the energetic particle fluxes are enhanced and the nominal orientation of the energetic particle streaming outward from the Sun (from 30 to 100 keV nuc⁻¹) abruptly reverses inward toward the Sun. This transient and punctuated evolution highlights the importance of magnetic field structures that connect the spacecraft to different acceleration sites, one of which is likely more distant from the Sun than PSP during the evolution of the CME. We discuss these characteristics and what they tell us about the source of the energetic particles. During this period, PSP was radially aligned with the Solar Terrestrial Relations Observatory A (STEREO-A), which measured the same CME when it passed 1 AU. The magnetic field measurements at both spacecraft are remarkably similar, indicating that the spacecraft are likely encountering the same portion of the magnetic structure that has not evolved significantly in transit. The energetic particle observations on the other hand, are quite different at STEREO-A, showing how transport effects have acted on the energetic particle populations and obscured the detailed properties present earlier in the development of the CME. This event provides a unique case study in how energetic particle populations evolve as CMEs propagate through the heliosphere.

Item Type:Article
Related URLs:
URLURL TypeDescription ItemIS⊙IS data and visualization tools ItemNASA Space Physics Data Facility
http://ccmc.gsfc.nasa.govRelated ItemGoddard Space Flight Community Coordinated Modeling Center
Joyce, C. J.0000-0002-3841-5020
McComas, D. J.0000-0001-6160-1158
Schwadron, N. A.0000-0002-3737-9283
Vourlidas, A.0000-0002-8164-5948
Christian, E. R.0000-0003-2134-3937
McNutt, R. L.0000-0002-4722-9166
Cohen, C. M. S.0000-0002-0978-8127
Leske, R. A.0000-0002-0156-2414
Mewaldt, R. A.0000-0003-2178-9111
Stone, E. C.0000-0002-2010-5462
Mitchell, D. G.0000-0003-1960-2119
Hill, M. E.0000-0002-5674-4936
Roelof, E. C.0000-0002-2270-0652
Allen, R. C.0000-0003-2079-5683
Szalay, J. R.0000-0003-2685-9801
Rankin, J. S.0000-0002-8111-1444
Desai, M. I.0000-0002-7318-6008
Giacalone, J.0000-0002-0850-4233
Matthaeus, W. H.0000-0001-7224-6024
Bale, S. D.0000-0002-1989-3596
Kasper, J. C.0000-0002-7077-930X
Additional Information:© ESO 2021. Article published by EDP Sciences. Received 17 November 2020; Accepted 12 May 2021; Published online 01 July 2021. Parker Solar Probe was designed, built, and is now operated by the Johns Hopkins Applied Physics Laboratory as part of NASA’s Living with a Star (LWS) program (contract NNN06AA01C). The IS⊙IS data and visualization tools are available to the community at:; data are also available via the NASA Space Physics Data Facility ( Simulation results have been provided by the Community Coordinated Modeling Center at Goddard Space Flight Center through their public Runs on Request system ( The ENLIL Model was developed by D. Odstrcil at the University of Colorado at Boulder. We thank the STEREO team for making the SEPT and MAG data used in this study publicly available. The SOHO/LASCO data used here are produced by a consortium of the Naval Research Laboratory (USA), Max-Planck-Institut fuer Aeronomie (Germany), Laboratoire d’Astronomie (France), and the University of Birmingham (UK). SOHO is a project of international cooperation between ESA and NASA. R.M.W. acknowledges support from NASA grant 80NSSC19K0914.
Group:Space Radiation Laboratory
Funding AgencyGrant Number
Subject Keywords:acceleration of particles; solar wind; magnetic fields
Record Number:CaltechAUTHORS:20210720-194559203
Persistent URL:
Official Citation:Energetic particle evolution during coronal mass ejection passage from 0.3 to 1 AU. C. J. Joyce, D. J. McComas, N. A. Schwadron, A. Vourlidas, E. R. Christian, R. L. McNutt, C. M. S. Cohen, R. A. Leske, R. A. Mewaldt, E. C. Stone, D. G. Mitchell, M. E. Hill, E. C. Roelof, R. C. Allen, J. R. Szalay, J. S. Rankin, M. I. Desai, J. Giacalone, W. H. Matthaeus, J. T. Niehof, W. de Wet, R. M. Winslow, S. D. Bale and J. C. Kasper. A&A, 651 (2021) A2; DOI:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:109934
Deposited By: Tony Diaz
Deposited On:21 Jul 2021 16:27
Last Modified:21 Jul 2021 16:27

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