Parker Solar Probe Observations of Energetic Particles in the Flank of a Coronal Mass Ejection Close to the Sun
Year: 2024
Type: article
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.
Source: The Astrophysical Journal
Authors: N. A. Schwadron, Stuart D. Bale, J. Bonnell, A. Case, M. Shen, E. R. Christian, C. M. S. Cohen, A. J. Davis, M. I. Desai, K. Goetz, J. Giacalone, M. E. Hill, J. C. Kasper, K. Korreck, D. Larson, R. Livi, T. Lim, R. A. Leske, O. Malandraki, D. Malaspina, W. H. Matthaeus, D. J. McComas, R. L. McNutt, R. A. Mewaldt, D. G. Mitchell, J. T. Niehof, M. Pulupa, Francesco Pecora, J. S. Rankin, C. Smith, E. C. Stone, J. R. Szalay, A. Vourlidas, M. E. Wiedenbeck, P. Whittlesey
Institutions: University of New Hampshire, Princeton University, Space Sciences Laboratory, University of California, Berkeley, Center for Astrophysics Harvard & Smithsonian, Goddard Space Flight Center, California Institute of Technology, The University of Texas at San Antonio, University of Minnesota, University of Arizona, Johns Hopkins University Applied Physics Laboratory, University of Michigan, National Aeronautics and Space Administration, National Observatory of Athens, Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing, University of Colorado Boulder, Laboratory for Atmospheric and Space Physics, University of Delaware
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $4,499
Award: G5966779717
OpenAlex ID: W4400823294