HR: 1425h
AN: SH23B-04    [Abstracts]
TI: Relationship between Halo Coronal Mass Ejections, EIT Flare Arcades, Coronal Neutral Line and Magnetic Clouds
AU: * Yurchyshyn, V
EM: vayur@bbso.njit.edu
AF: Big Bear Solar Observatory, 40386 North Shore Lane, Big Bear City, CA 92314, United States
AB: Coronal mass ejections (CMEs) are the most important solar drivers of geomagnetic storms. Their interplanetary counterparts, interplanetary CMEs (ICMEs), can be detected in-situ, for example, by ACE and Wind spacecraft. An ICME usually exhibits a complex structure that very often includes a magnetic cloud (MC), which is thought to be a magnetic flux rope, capable of providing prolonged periods of southward interplanetary magnetic field at 1 AU. The magnitude of the storm depends, in general, on the orientation and intensity of the magnetic field in the ejecta. In this presentation we will discuss how the size of the geomagnetic storm can be predicted from coronagraph images. There is observational evidence that the orientation of a halo CME elongation corresponds to the orientation of the underlying flux rope, while the intensity of the magnetic field in an ejecta seems to be related to the CME speed. Here we compare orientation angles of elongated LASCO halo CMEs, EIT flare arcades (post flare loop system), the local tilt of the heliospheric current sheet and the corresponding MCs. We report that i) for about 64% of CME-ICME events, a good correspondence was found between the orientation angles of CMEs and MC; ii) 20 out of 25 CMEs (80%) were oriented along the axis of the corresponding EIT flare arcade; and iii) 19 out of 25 (76%) of CMEs are co- aligned with the heliospheric current sheet at 2.5 solar radii. In the final part of the presentation we will discuss the applications of our findings to CME modeling, space weather forecast and possible future studies.
UR: http://www.bbso.njit.edu/~vayur/
DE: 7513 Coronal mass ejections (2101)
DE: 7524 Magnetic fields
DE: 7924 Forecasting (2722)
DE: 7974 Solar effects
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2007 Fall Meeting