October 27, 2017, 1:00 pm - 2:00 pm

October 27, 1:00 pm - 2:00 pm

Modeling study of the geospace system response to a solar wind dynamic pressure enhancement

Doga Can Su Ozturk (Climate & Space Sciences and Engineering University of Michigan)

The fields and currents at the high latitude ionosphere are very sensitive to external drivers, hence the solar wind dynamic pressure enhancements significantly perturb the global magnetosphere-ionosphere-thermosphere (M-I-T) system. In order to understand the large-scale dynamic processes in the M-I-T system due to the compression from solar wind, the 17 March 2015 event was studied in detail using global numerical models. This storm was one of the most geoeffective events of the solar cycle 24 with a minimum Dst of -222 nT. The Wind spacecraft recorded an increment in the solar wind dynamic pressure, from 2 nPa to 12 nPa within 3 minutes, while the IMF Bz stayed northward. The University of Michigan Block Adaptive Tree Solarwind Roe Upwind Scheme (BATS'R'US), global MHD code was utilized to study the generation and propagation of perturbations associated with the compression of the magnetosphere system. In addition, the high-resolution electric field potential output from the self-consistent MHD model was used to drive the Global Ionosphere Thermosphere Model (GITM). During the compression, the electric field potentials were significantly altered, affecting the ion convection patterns. Correspondingly, the ion, electron and neutral temperatures were enhanced, whereas the electron density dropped at locations where the flow speeds were highest. The comparison of simulation results with Poker Flat Incoherent Scatter Radar (PFISR) observations showed similar response but underestimated temperature and density values.