Parker Solar Probe Observations of Energetic Particles in the Flank of a Coronal Mass Ejection Close to the Sun

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Authors

Nathan A. Schwadron, University of New Hampshire, DurhamFollow
Stuart D. Bale, University of California, Berkeley
J Bonnell, University of California, Berkeley
A Case, Harvard-Smithsonian Center for Astrophysics
M Shen, Princeton University
E R. Christian, Goddard Space Flight Center
C M S Cohen, California Institute of Technology
A J. Davis, California Institute of Technology
M I. Desai, University of Texas at San Antonio
K Goetz, University of Minnesota
J Giacalone, University of Arizona
M E. Hill, Applied Physics Laboratory
J C. Kasper, University of Michigan
K Korreck, NASA HQ
D Larson, University of California at Berkeley
R Livi, University of California at Berkeley
T Lim, University of New Hampshire, Durham
R A. Leske, California Institute of Technology
O Malandraki, National Observatory of Athens
D Malaspina, University of Colorado
W H. Matthaeus, University of Delaware
D J. McComas, Princeton University
R L. McNutt, Applied Physics Laboratory
R A. Mewaldt, California Institute of Technology
D G. Mitchell, Applied Physics Laboratory
Jonathan T. Niehof, University of New Hampshire, DurhamFollow
M. Pulupa, University of California at Berkeley
Francesco Pecora, University of Delaware Newark
J. S. Rankin, Princeton University
Charles Smith, University of New Hampshire, DurhamFollow
E. C. Stone, California Institute of Technology
J. R. Szalay, Princeton University
A. Vourlidas, Applied Physics Laboratory
M. E. Wiedenbeck, California Institute of Technology
P. Whittlesey, University of California at Berkeley

Abstract

We present an event observed by Parker Solar Probe (PSP) at ∼0.2 au on 2022 March 2 in which imaging and in situ measurements coincide. During this event, PSP passed through structures on the flank of a streamer blowout coronal mass ejection (CME) including an isolated flux tube in front of the CME, a turbulent sheath, and the CME itself. Imaging observations and in situ helicity and principal variance signatures consistently show the presence of flux ropes internal to the CME. In both the sheath and the CME interval, the distributions are more isotropic, the spectra are softer, and the abundance ratios of Fe/O and He/H are lower than those in the isolated flux tube, and yet elevated relative to typical plasma and solar energetic particle abundances. These signatures in the sheath and the CME indicate that both flare populations and those from the plasma are accelerated to form the observed energetic particle enhancements. In contrast, the isolated flux tube shows large streaming, hard spectra, and large Fe/O and He/H ratios, indicating flare sources. Energetic particle fluxes are most enhanced within the CME interval from suprathermal through energetic particle energies (∼keV to >10 MeV), indicating particle acceleration, as well as confinement local to the closed magnetic structure. The flux-rope morphology of the CME helps to enable local modulation and trapping of energetic particles, in particular along helicity channels and other plasma boundaries. Thus, the CME acts to build up energetic particle populations, allowing them to be fed into subsequent higher-energy particle acceleration throughout the inner heliosphere where a compression or shock forms on the CME front.

Department

Physics

Publication Date

7-1-2024

Journal Title

The Astrophysical Journal

Publisher

American Astronomical Society

Digital Object Identifier (DOI)

https://dx.doi.org/10.3847/1538-4357/ad527f

Document Type

Article

Recommended Citation

N. A. Schwadron et al 2024 ApJ 970 98 DOI 10.3847/1538-4357/ad527f

Comments

This is an open access article published by American Astronomical Society in The Astrophysical Journal in 2024, available online: https://dx.doi.org/10.3847/1538-4357/ad527f