SM31D-4233:
MHD modeling of ULF wave activity for three Van Allen Probes storms of 2012 and 2013
Wednesday, 17 December 2014
Jan Paral1, Mary K Hudson1, Brian T Kress1, John R Wygant2 and Michael James Wiltberger3, (1)Dartmouth College, Hanover, NH, United States, (2)University of Minnesota Twin Cities, Minneapolis, MN, United States, (3)National Center for Atmospheric Research, High Altitude Observatory, Boulder, CO, United States
Abstract:
Recent numerical studies suggest that enhanced Ultra Low Frequency (ULF) wave activity is necessary to explain electron losses deeper inside the magnetosphere than magnetopause incursion following CME-shock arrival. A combination of radial transport and magnetopause shadowing can account for loses observed at radial distances into L=4.5, well within the computed magnetopause location. We compare ULF wave power from the EFW electric field instrument on the Van Allen Probes from for the October 8 2013 storm with ULF wave power simulated using the Lyon–Fedder–Mobarry (LFM) global MHD magnetospheric simulation code. The model is driven by upstream solar wind conditions measured at the ARTEMIS spacecraft for the October 8 2013 storm to obtain global spatial and temporal structure of ULF waves. We show that the global MHD model provides a good estimate of field topology and the frequency range along the Van Allen Probes orbit, comparable to electron drift periods affecting radial transport.
