Most studies of the magnetosphere have been carried out by considering primarily the north-south (Bz) component of the interplanetary magnetic field (IMF) and most of those have considered intervals with southward IMF (Bz<0). Recent discoveries have revealed anomalous thermospheric neutral density signatures caused by intense deposition of Poynting flux delivered over very localized regions under conditions that are normally considered benign. These studies have shown that relatively modest IMF By-driven localized heating at storm-onset generates neutral thermospheric disturbances that had not previously been explained. In addition studies using data from DMSP satellites demonstrated large yet localized dayside energy input. MHD simulation results for one case suggest that the localized enhanced Poynting fluxes in the southern hemisphere map to a flank magnetopause reconnection region. Most of these events are associated with dominant in-the-ecliptic interplanetary magnetic field (IMF) values, often, but not exclusively, while the IMF Bz is northward (Bz>0). The objectives of this proposal are to verify the source region (magnetopause merging versus bow shock) of the Poynting flux-related dayside field-aligned currents (FACs), determine their ionospheric distribution, and examine the relative local and global impact of the Poynting flux energy input on the magnetosphere-ionosphere-thermosphere system. The influences of solar ejecta and high-speed streams will be distinguished and investigated for seasonal and hemispheric differences. The study will employ both data analysis from multiple satellites, ground based observations from radar and the AMIE technique and tie all the observations together with global magnetohydrodynamic simulations.
This research potentially transforms the way the space science community views the effects of non-southward IMF on the geospace environment. It is at the forefront of system science in exploring the influence of non-southward IMF on the field-aligned currents that deliver focused energy to dayside regions. This is an understudied area of space physics. It also has practical application to problems related to satellite drag.
