Magnetospheric ULF wave generation during an ICME-magnetosphere interaction

Ultra-low-frequency waves are a useful diagnostic for measuring momentum and energy transfer into and within the inner magnetosphere. We use the OpenGGCM MHD code at NASA CCMC to represent ULF wave generation in 4 MLT sectors (noon, dusk, midnight, and dawn) prior to and during the storm of September 18, 2000. The event is divided in two parts: the early phase of the ICME passage (Sept 17, 12:00-24:00 UT including mainly the shock and sheath) and a long-lasting Northward-Bz interval (Sept 18, 00:00-15:00 UT including mainly the magnetic cloud). During the early phase of the ICME, power spectral analysis of the electric and magnetic fields shows harmonic patterns which are interpreted as signatures of field-line resonances and traveling ULF waves excited by the ICME impact. We compare the simulation electromagnetic and plasma-velocity fields with measurements from GOES and POLAR in the magnetosphere, Geotail in the magnetosheath, and WIND in the solar wind.