A statistical study of the plasma and composition distribution inside magnetic clouds: 1998-2011
Document Type
Article
Publication Date
4-1-2020
Abstract
A comprehensive analysis of plasma and composition characteristics inside magnetic clouds (MCs) observed by the Advanced Composition Explorer spacecraft from 1998 February to 2011 August is presented. The results show that MCs have specific interior structures, and MCs of different speeds show differences in composition and structure. Compared with the slow MCs, fast MCs have enhanced mean charge states of iron, oxygen, silicon, magnesium, O7+ O6+, C6+ C5+, C6+ C4+, and Fe. 16+ Fe total values. For ionic species in fast MCs, a higher atomic number represents a greater enhancement of mean charge state than slow MCs. We also find that both the fast and slow MCs display bimodal structure distribution in the mean iron charge state (aQnFe), which suggests that the existence of flux rope prior to the eruption is common. Furthermore, the aQnFe, Fe.16+ Fe total, and O + O +7 6 ratio distribution inside fast MCs have the feature that the posterior peak is higher than the anterior one. This result agrees with the ``standard model'' for coronal mass ejection/flares, by which magnetic reconnection occurs beneath the flux rope, thereby ionizing the ions of the posterior part of the flux rope sufficiently by high-energy electron collisions or by direct heating in the reconnection region.
Keywords
Solar wind, Solar coronal mass ejections, Interplanetary physics, Solar physics, Solar storm, Solar flares, Solar filament eruptions, Solar filaments
Divisions
PHYSICS
Funders
National Scientific Foundation of China [Grant No: NSFC 11533009, 11973086],University of Malaya Faculty of Science [Grant No: GPF040B-2018],Chinese Academy of Sciences [Grant No: XDA-17040507]
Publication Title
Astrophysical Journal
Volume
893
Issue
2
Publisher
IOP Publishing Ltd
Publisher Location
TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND