Comparison of the Composition of ICMEs from Active Regions and Quiet-Sun Regions

Li, Jinrong; Song, Hongqiang; Lv, Qi; Fu, Hui; Li, Leping; Zheng, Ruisheng; Chen, Yao

doi:10.3847/1538-4357/acba90

Cited by 3 publications

(3 citation statements)

References 69 publications

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“…ICMEs can result in extreme space weather effects that have an impact on our production and life (Gosling et al 1991;Zhang et al 2007;Xu et al 2019;Song et al 2021). A significant number of ICMEs are detected near 1 au that originate from active regions around the solar maximum (Fu et al 2017;Li et al 2023). Thus, the temporal variation of ICMEs and HCMEs is also worth exploring.…”

Section: Conclusion and Discussionmentioning

confidence: 99%

Hemispheric Distribution of Halo Coronal Mass Ejection Source Locations

Zhang,

Deng,

Deng

et al. 2024

ApJ

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The hemispheric asymmetry of solar activity is one of the essential physical consequences of the interior dynamo process. However, the hemispheric distribution of halo coronal mass ejection (HCME) source locations has not been investigated in detail. Based on the HCME catalog identified from the Large Angle and Spectrometric Coronagraph Experiment on board the Solar and Heliospheric Observatory, we perform a hemispheric distribution analysis of the HCME source locations from 1996 April to 2022 June. The main results are as follows. (1) The HCME source locations are confined to the active region belt, and there is no “rush to the poles” phenomenon that is unique to large-scale magnetic activity. (2) The HCME source locations exhibit a general hemispheric asymmetry, and autoregressive moving-average model results show that the asymmetry of HCME source locations is significantly different from that of sunspot activity. (3) The hemispheric distribution of cycle 24 is different from that of cycle 23, potentially as a result of the heliospheric dynamic pressure having noticeably decreased after the polarity reversal of cycle 23. Our results contribute to a more comprehensive understanding of the hemispheric asymmetry of energetic magnetic structures and give a new perspective on understanding the geoeffectiveness of HCMEs.

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Section: Conclusion and Discussionmentioning

confidence: 99%

Hemispheric Distribution of Halo Coronal Mass Ejection Source Locations

Zhang,

Deng,

Deng

et al. 2024

ApJ

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“…In this paper, we use the catalog of Richardson and Cane (Richardson & Cane 2004 based on ACE measurements, 5 as the heavy-ion data are from ACE/SWICS. The SWICS team provides the optimal data from 1998 February to 2011 August, during which the catalog lists 319 ICMEs in total (e.g., Feng et al 2018;Song et al 2021a;Li et al 2023).…”

Section: Icme Catalogmentioning

confidence: 99%

Comparison of Ion–Proton Differential Speed between Interplanetary Coronal Mass Ejections and Solar Wind near 1 au

Zhang,

Song,

Zhang

et al. 2024

ApJ

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The elemental abundance of interplanetary coronal mass ejections (ICMEs) and solar wind near 1 au is often adopted to represent the abundance in the corresponding coronal sources. However, the absolute abundance of heavy ions (relative to hydrogen) near 1 au might be different from the coronal abundance due to the ion–proton differential speed (V ip ). To illustrate the V ip characteristics and explore whether it influences the absolute abundance analysis for ICMEs and solar wind, we perform a statistical study on the V ip for He2+, C5+, O6+, and Fe10+ in both ICMEs and solar wind based on measurements of Advanced Composition Explorer. The results show that the V ip is negligible within ICMEs and slow solar wind (< 400 km s−1), while obvious in the intermediate (400–600 km s−1) and fast wind (> 600 km s−1). Previous studies showed that the V ip in ICMEs keeps negligible during propagation from 0.3 to 5 au, but in solar wind it increases with the decreasing heliocentric distance. Therefore, it might be questionable to infer the absolute abundance of coronal sources through in situ abundance near 1 au for solar wind. Fortunately, the ion–oxygen (O6+) differential speed (V io ) is negligible for He2+, C5+, and Fe10+ within both ICMEs and solar wind, and previous studies suggested that the V io does not vary significantly with the heliocentric distance. This indicates that various heavy ions always flow at the same bulk speed and their relative abundance (relative to oxygen) near 1 au can represent the coronal abundance for both ICMEs and solar wind.

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“…These A He values are in large contrast to the solar wind, which is primarily depleted compared to photospheric values (Ogilvie & Hirshberg 1974;Aellig et al 2001;Kasper et al 2007Kasper et al , 2012Alterman & Kasper 2019;Alterman et al 2021;Yogesh & Srivastava 2021). Moreover, recent studies find that, like the solar wind, CMEs also exhibit a solar-cycle dependence in their composition (Song et al 2021(Song et al , 2022Li et al 2023). The changes in abundance have been connected to differences among their source regions (i.e., active regions in comparison to quiet Sun) whose thermal structure, elemental composition, and appearance across the solar cycle can be markedly different (see recent summary in Norton et al 2023).…”

Section: Introductionmentioning

confidence: 97%

Helium Abundance Periods Observed by the Solar Probe Cup on Parker Solar Probe: Encounters 1–14

Johnson,

Rivera,

Niembro

et al. 2024

ApJ

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Parker Solar Probe is a mission designed to explore the properties of the solar wind closer than ever before. Detailed particle observations from the Solar Probe Cup (SPC) have primarily focused on examining the proton population in the solar wind. However, several periods throughout the Parker mission have indicated that SPC has observed a pronounced and distinctive population of fully ionized helium, He2+. Minor ions are imprinted with properties of the solar wind’s source region, as well as mechanisms active during outflow, making them sensitive markers of its origin and formation at the Sun. Through a detailed analysis of the He2+ velocity distributions functions, this work examines periods where significant and persistent He2+ peaks are observed with SPC. We compute the helium abundance and examine the stream’s bulk speed, density, temperature, magnetic field topology, and electron strahl properties to identify distinctive solar-wind features that can provide insight to their solar source. We find that nearly all periods exhibit an elevated mean helium composition (8.34%) compared to typical solar wind and a majority (∼87%) of these periods are connected to coronal mass ejections (CMEs), with the highest abundance reaching 23.1%. The helium abundance and number of events increases as the solar cycle approaches maximum, with a weak dependence on speed. Additionally, the events not associated with a CME are clustered near the heliospheric current sheet, suggesting they are connected to streamer belt outflows. However, there are currently no theoretical explanations that fully describe the range of depleted and elevated helium abundances observed.

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Comparison of the Composition of ICMEs from Active Regions and Quiet-Sun Regions

Cited by 3 publications

References 69 publications

Hemispheric Distribution of Halo Coronal Mass Ejection Source Locations

Hemispheric Distribution of Halo Coronal Mass Ejection Source Locations

Comparison of Ion–Proton Differential Speed between Interplanetary Coronal Mass Ejections and Solar Wind near 1 au

Helium Abundance Periods Observed by the Solar Probe Cup on Parker Solar Probe: Encounters 1–14

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