HR: 1330h
AN: SH53A-11    [Abstracts]
TI: Identifying and Characterizing ICMEs Using Total Perpendicular Pressure
AU: * Jian, L
EM: lanjian@ucla.edu
AF: University of California Los Angeles, Institute of Geophysics & Planetary Physics, 405 Hilgard Avenue, Los Angeles, CA 90095-1567 United States
AU: Russell, C T
EM: ctrussell@igpp.ucla.edu
AF: University of California Los Angeles, Institute of Geophysics & Planetary Physics, 405 Hilgard Avenue, Los Angeles, CA 90095-1567 United States
AU: Gosling, J T
EM: jgosling@lanl.gov
AF: Los Alamos National Laboratory, SM-30, Bikini Atoll Rd., Los Alamos, NM 87545 United States
AU: Luhmann, J G
EM: jgluhman@ssl.berkeley.edu
AF: University of California Berkeley, Space Sciences Laboratory, 7 Gauss Way, Berkeley, CA 94720-7450 United States
AB: It is conventional wisdom that only about one-third of Interplanetary Coronal Mass Ejections are found to contain a magnetic cloud. However, one of the most secure identifying features of an ICME is the presence of a cloud and is used by many ICME researchers to classify ICMEs. In order to determine how many ICME observations do or do not include entry into a cloud, we must have a reliable method of defining an ICME encounter that does not depend on the presence of a rotating magnetic field. Total perpendicular pressure can be used to distinguish ICMEs from other solar wind disturbances such as stream interactions without examining the direction of the magnetic field on its temporal behavior. We have compared our identifications with those of other groups and conclude that this identifier is quite effective. We find that many of the ICMEs that do not exhibit rotating magnetic fields are encountered far to the side of the center of the ICME, thus missing the cloud. Nevertheless there are ICMEs with strong field enhancements that do not exhibit rotations. There may be magnetic clouds but do not appear to be nice ropes.
DE: 2100 INTERPLANETARY PHYSICS
DE: 2111 Ejecta, driver gases, and magnetic clouds
DE: 2134 Interplanetary magnetic fields
DE: 7513 Coronal mass ejections
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2005 Joint Assembly