HR: 0800h
AN: SA51B-0240    [Abstracts]
TI: Solar wind low-energy energetic ion enhancements: a tool for forecasting large geomagnetic storms
AU: * Smith, Z
EM: Zdenka.smith@noaa.gov
AF: Zdenka Smith, NOAA/SEC 325 Broadway, Boulder, CO 80305 United States
AU: Murtagh, W
EM: William.Murtagh@noaa.gov
AF: Zdenka Smith, NOAA/SEC 325 Broadway, Boulder, CO 80305 United States
AU: Detman, T R
EM: thomas.r.detman@noaa.gov
AF: Zdenka Smith, NOAA/SEC 325 Broadway, Boulder, CO 80305 United States
AB: The use of energetic ion enhancements (EIEs) as a tool for forecasting large geomagnetic storms was investigated in a previous study. The study was based on a data set in the rise and maximum of solar cycle 23 (Feb. 1998 - Dec. 2000). An excellent correlation was found between large geomagnetic storms (storms with Kp $>$6) and the peak flux of large energetic ion enhancements. As there are many more substantial EIEs than large geomagnetic storms, other characteristics were sought to help determine which of the EIEs are likely to be followed by large storms. These characteristics included the nature of the IP driver (whether transient or co-rotating high speed stream), and whether the EIEs result from complex solar and/or interplanetary activity. Here we present a forecasting technique using an additional parameter, the magnitude of the total magnetic field at the time of the shock arrival. This improves the identification of the EIEs that are likely to be followed by large storms. The success of this forecasting technique, and the warning times obtained, are presented for the time period of the original study and compared to the declining phase of the solar cycle. Note that the original study used data from the ACE/EPAM/LEMS-30 instrument. This was replaced in 2002 by the LEMS-120 instrument. We identify the equivalent EIE flux thresholds for the LEMS-120 instrument.
DE: 2114 Energetic particles, heliospheric (7514)
DE: 2134 Interplanetary magnetic fields
DE: 2139 Interplanetary shocks
DE: 2164 Solar wind plasma
DE: 2194 Instruments and techniques
SC: SPA-Aeronomy [SA]
MN: 2004 AGU Fall Meeting