Particle entry into the inner magnetosphere during duskward IMF B-y: Global three-dimensional electromagnetic full particle simulations

摘要

The change of the interplanetary magnetic field ( IMF) direction from northward to duskward has an important impact on the inner magnetosphere. This impact is analyzed with the help of a new parallel version of the global three-dimensional full particle simulation code. For northward IMF, bands of weak magnetic field ( sash) form poleward of the cusp at high latitudes in each hemisphere. These sashes move to the equator ( within opposite quadrants) as the IMF rotates duskward and merge into one another to form the characteristic "Crosstail-S'' within the neutral sheet of the magnetotail. These macroscopic magnetic patterns ( sashes and Crosstail-S) evidenced herein are in a good agreement with results of previous 3D MHD simulations and experimental observations. Moreover, the analysis of particle fluxes shows that "sashes'' and "Crosstail-S'' act as magnetic groove to facilitate the entry and injection of magnetosheath particles into the inner magnetosphere. Injected particles are accelerated after the IMF changes its direction from northward to duskward.