HR: 1330h
AN: SH42A-0480    [PDF]
TI: Multispacecraft Observations of Few-MeV SEP Ion Event Onsets Near Earth
AU: Eastman, T E
EM: plasmas@starpower.net
AF: Plasmas International, Silver Spring, Silver Spring, MD 20910 United States
AU: * Christon, S P
EM: spchriston@aol.com
AF: Focused Analysis and Research, Columbia, Columbia, MD 21044 United States
AU: Decker, R B
EM: robert.decker@jhuapl.edu
AF: Johns Hopkins University/, Applied Physics Laboratory, Laurel, MD 20723 United States
AU: Roelof, E C
EM: edmond.roelof@jhuapl.edu
AF: Johns Hopkins University/, Applied Physics Laboratory, Laurel, MD 20723 United States
AB: Few-MeV-energy SEP proton flux onsets observed in interplanetary space near Earth are used to investigate the effectiveness of a single spacecraft stationed at the sunward L1 libration point ($\sim$230 Re) to provide complete early warning information about Solar Energetic Particle (SEP) events. Knowledge of the behavior and distribution of few-MeV-energy protons at onset aids development of asset protection, predictive capabilities, and understanding of magnetospheric disturbances related to SEP appearance at Earth. Widely separated spacecraft, ACE near L1 and GOES-8, Geotail, and IMP-8 nearer to Earth ($\sim$6.6-44 Re), provided simultaneous SEP observations from late 1997 to the present. A number of cases of spatial-temporal intensity variations between L1 and nearer-Earth observations are presented. Cases presented demonstrate large-scale transport characteristics both consistent and inconsistent with simple outward radial propagation (i.e., convection with the solar wind) of a locally planar feature over the $\sim$230 Re ($\sim$0.01 AU) maximum separation distance.
DE: 2100 INTERPLANETARY PHYSICS
DE: 2400 IONOSPHERE
DE: 2700 MAGNETOSPHERIC PHYSICS
DE: 7500 SOLAR PHYSICS, ASTROPHYSICS, AND ASTRONOMY
DE: 7800 SPACE PLASMA PHYSICS
SC: SPA - Solar and Heliospheric Physics [SH]
MN: 2003 Fall Meeting