Self‐consistent inner magnetosphere simulation driven by a global MHD model

We present results from a one‐way coupling between the kinetic Ring Current Atmosphere Interactions Model with Self‐Consistent B field (RAM‐SCB) and the Space Weather Modeling Framework (SWMF). RAM‐SCB obtains plasma distribution and magnetic field at model boundaries from the Block Adaptive Tree Solar Wind Roe Upwind Scheme (BATS‐R‐US) magnetohydrodynamics (MHD) model and convection potentials from the Ridley Ionosphere Model within SWMF. We simulate the large geomagnetic storm of 31 August 2005 (minimum SYM‐H of −116 nT). Comparing SWMF output with Los Alamos National Laboratory geostationary satellite data, we find SWMF plasma to be too cold and dense if assumed to consist only of protons; this problem is alleviated if heavier ions are considered. With SWMF inputs, we find that RAM‐SCB reproduces well storm time magnetosphere features: ring current morphology, dusk side peak, pitch angle anisotropy, and total energy. The RAM‐SCB ring current and Dst are stronger than the SWMF ones and reproduce observations much better. The calculated field‐aligned currents (FAC) compare reasonably well with 2 h averaged pictures from Iridium satellite data. As the ring current peak rotates duskward in the storm main phase, the region 2 FACs rotate toward noon, a feature also seen in observations. Finally, the RAM‐SCB magnetic field outperforms both the dipole and the BATS‐R‐US field at Cluster and Polar spacecraft locations. This study shows the importance of a kinetic self‐consistent approach and the sensitive dependence of the storm time inner magnetosphere on plasma sheet conditions and the cross polar cap potential. The study showcases the RAM‐SCB capability as an inner magnetosphere module coupled with a global MHD model.