The Streamer Blowout Origin of a Flux Rope and Energetic Particle Event Observed by Parker Solar Probe at 0.5 au

Abstract

The distribution of spacecraft in the inner heliosphere during 2019 March enabled comprehensive observations of an interplanetary coronal mass ejection (ICME) that encountered Parker Solar Probe (PSP) at 0.547 au from the Sun. This ICME originated as a slow (∼311 km s −1 ) streamer blowout (SBO) on the Sun as measured by the white-light coronagraphs on board the Solar TErrestrial RElations Observatory-A and the Solar and Heliospheric Observatory. Despite its low initial speed, the passage of the ICME at PSP was preceded by an anisotropic, energetic (100 keV/n) ion enhancement and by two interplanetary shocks. The ICME was embedded between slow (∼300 km s −1 ) solar wind and a following, relatively high-speed (∼500 km s −1 ), stream that most likely was responsible for the unexpectedly short (based on the SBO speed) ICME transit time of less than ∼56 hr between the Sun and PSP, and for the formation of the preceding shocks. By assuming a graduated cylindrical shell (GCS) model for the SBO that expands self-similarly with time, we estimate the propagation direction and morphology of the SBO near the Sun. We reconstruct the flux-rope structure of the in situ ICME assuming an elliptic-cylindrical topology and compare it with the portion of the 3D flux-rope GCS morphology intercepted by PSP. ADAPT-WSA-ENLIL-Cone magnetohydrodynamic simulations are used to illustrate the ICME propagation in a structured background solar wind and estimate the time when PSP established magnetic connection with the compressed region that formed in front of the ICME. This time is consistent with the arrival at PSP of energetic particles accelerated upstream of the ICME.

PSP/IS$\odot$IS Observation of a Solar Energetic Particle Event Associated With a Streamer Blowout Coronal Mass Ejection During Encounter 6

“…This closed structure observed during the period of bidirectional electrons coincides with the SBO-CME arrival time. During its earlier orbits, PSP encountered SBO-CMEs (Korreck et al 2020;Lario et al 2020;Nieves-Chinchilla et al 2020) and SEP enhancements associated with SBO-CMEs were also observed (Giacalone et al 2020;Lario et al 2020;Mitchell et al 2020a), consistent with our observation.…”

Magnetic Structure and Propagation of Two Interacting CMEs From the Sun to Saturn

“…G. Richardson, 2014;Riley et al, 2000). Data from the more recently launched Parker Solar Probe, BepiColombo, and Solar Orbiter have resulted in several studies of CMEs measured between the Sun and 1 AU (e.g., E. E. Davies et al, 2021;Korreck et al, 2020;Lario et al, 2020;Nieves-Chinchilla et al, 2020;Zhao et al, 2020;Weiss et al, 2021). Considerable results were also achieved using data from spacecraft, such as Pioneer 10/11 and Voyager 1/2, that were launched on escape trajectories out of the solar system and that have provided valuable information on the behavior of ICMEs at progressively larger heliocentric distances (e.g., Burlaga et al, 2001;C.…”

Predicting the Magnetic Fields of a Stealth CME Detected by Parker Solar Probe at 0.5 AU

“…The encouraging results of the magnetic field hindcast prediction presented in this work suggest that these events could be accurately forecast even if their exact source region remains elusive in on-disc imagery. Certainly, in this and other reported cases off-limb observations were crucial in connecting a stealth CME at the Sun with its interplanetary counterpart (e.g., Korreck et al 2020;Lario et al 2020;O'Kane et al 2021). Thus, this study highlights the importance of continuous observations of the solar disc and corona away from the Sun-Earth line, not only to enable more accurate space weather forecasts, but also to shed light on the complex characteristics and dynamics of stealthy CMEs that, albeit slow, have potential for considerable geoeffectiveness.…”