科研之友
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摘要
As a kind of eruptive phenomenon associated with coronal mass ejections (CMEs), solar eruptive filaments are thought to be parallel to the axis of surrounding arcade coronal magnetic fields that erupt and develop into interplanetary magnetic clouds (MCs). By investigating three events from 2000 August, 2003 October, and 2003 November, we estimate the axial orientations of the MCs and make a quantitative comparison with the filament orientations. By defining "tilt angle'' as the angle between projected orientation on the plane of the sky and the ecliptic, we find that the tilt angles of these MCs are about 30 degrees, 60 degrees, and 55 degrees, respectively. However, H alpha images show that the associated filaments were all highly curved. The tilt angles of the long axes of these filaments prior to their eruption vary in a range that corresponds to tangents along the entire curved path of the filaments. Comparison between the MCs and filaments shows that for the first and third events, the estimated MC tilt angles are within the range of tilt angles of the associated filaments and almost parallel to the central parts of the filaments. But for the second event, the MC tilt angle is outside the range. This work suggests that (1) the curvature of filaments should be considered in studying the relation between filament and MC orientations, (2) inconsistencies between them do occur, even if the filament curvature is taken into account, and (3) the largest deviation in the tilt angle between MCs and their associated filaments occurs for those MCs whose orientations are not perpendicular to the Earth-Sun line, indicating that the measured part of the MC is not its leading front.
- 出版日期2006-11-10
- 单位中国科学院国家天文台
