HR: 0830h
AN: SH21B-0133    [PDF]
TI: What Defines an Interplanetary Coronal Mass Ejection?
AU: Shinde, A A
EM: aniketa@ucla.edu
AF: Institute of Geophysics, University of California 405 Hilgard Ave, Los Angeles, CA 90095-1567 United States
AU: * Russell, C T
EM: ctrussell@igpp.ucla.edu
AF: Institute of Geophysics, University of California 405 Hilgard Ave, Los Angeles, CA 90095-1567 United States
AB: Because the majority of spacecraft that observe Interplanetary Coronal Mass Ejections (ICMEs) have been in the neighborhood of the Earth while the best observations of Coronal Mass Ejection (CME) are of ejections orthogonal to the Earth-sun line, the observation of a CME is not a prerequisite for defining an ICME. Several observers (e.g. D. Larson, R. Lepping and ourselves) have compiled lists of ICMEs based on somewhat subjective criteria but derived from a common database, Wind and ACE solar wind and IMF measurements. Some of the criteria include a stronger than ambient magnetic field, a rotating magnetic field, low beta, low ion temperature, declining velocity profile and others. We examine these lists to determine what properties are possessed by consensus ICMEs and what produces an ambiguous ICME. Not all ICMEs that have been identified are low beta structures, not all of them are expanding and not all produce shocks. At times even the magnetic profile of ICMEs is quite flat. One of the major objectives of the in-situ investigations on STEREO should be to use quadrature data to understand the variety of apparent manifestations of ICMEs at 1 AU.
DE: 2134 Interplanetary magnetic fields
DE: 2164 Solar wind plasma
DE: 7513 Coronal mass ejections
SC: SPA - Solar and Heliospheric Physics [SH]
MN: 2003 Fall Meeting