Compositional Metrics of Fast and Slow Alfvénic Solar Wind Emerging from Coronal Holes and Their Boundaries

Autor: Tamar Ervin, Stuart D. Bale, Samuel T. Badman, Yeimy J. Rivera, Orlando Romeo, Jia Huang, Pete Riley, Trevor A. Bowen, Susan T. Lepri, Ryan M. Dewey
Jazyk: angličtina
Rok vydání: 2024
Předmět:
Zdroj: The Astrophysical Journal, Vol 969, Iss 2, p 83 (2024)
Druh dokumentu: article
ISSN: 1538-4357
DOI: 10.3847/1538-4357/ad4604
Popis: We seek to understand the composition and variability of fast solar wind (FSW) and slow Alfvénic solar wind emerging from coronal holes (CHs). We leverage an opportune conjunction between Solar Orbiter and Parker Solar Probe (PSP) during PSP Encounter 11 to include compositional diagnostics from the Solar Orbiter Heavy Ion Sensor as these variations provide crucial insights into the origin and nature of the solar wind. We use potential field source surface and magnetohydrodynamic models to connect the observed plasma at PSP and Solar Orbiter to its origin footpoint in the photosphere and compare these results with the in situ measurements. A very clear signature of a heliospheric current sheet crossing as evidenced by enhancements in low first ionization potential (FIP) elements, ion charge state ratios, proton density, low Alfvénicity, and polarity estimates validates the combination of modeling, data, and mapping. We identify two FSW streams emerging from small equatorial CHs with low ion charge state ratios, low FIP bias, high Alfvénicity, and low footpoint brightness, yet anomalously low alpha particle abundance for both streams. We identify high-Alfvénicity slow solar wind emerging from the overexpanded boundary of a CH having intermediate alpha abundance, high Alfvénicity, and dips in ion charge state ratios corresponding to CH boundaries. Through this comprehensive analysis, we highlight the power of multi-instrument conjunction studies in assessing the sources of the solar wind.
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