Sources, transport, and distributions of plasma sheet ions and electrons and dependences on interplanetary parameters under northward interplanetary magnetic field

We have investigated the Geotail data statistically to understand the particle sources, transport, and spatial distributions of the plasma sheet ions and electrons of different energies during northward interplanetary magnetic field ( IMF), and their dependences on the solar wind density (N-sw), the solar wind speed (V-sw), and the magnitude of the northward IMF B-z (vertical bar B-z,B-IMF vertical bar). We find that the plasma sheet becomes colder and denser, indicating a larger increase in the cold than in the hot population, with increasing N-sw or vertical bar B-z,B-IMF vertical bar or with decreasing V-sw. The cold population dominates the region near the flanks while the hot population dominates the near-midnight region, which is consistent with the plasma sheet plasma being a mixture of cold particles coming from the flanks and hot particles from the distant-tail. The phase space densities show that the flank source strongly depends on vertical bar B-z,B-IMF vertical bar, while the tail source strongly depends on V-sw. Cold particles from the dawn flank to midnight increase significantly with decreasing V-sw, but no significant changes are seen near the dusk flank, suggesting a dependence of the solar wind entry through the dawn flank on V-sw. The comparisons between the distributions of the phase space density and the electric and magnetic drift paths estimated from the observations indicate that the thermal and high-energy particles are mainly transported by electric and magnetic drift, while other transport mechanisms, such as diffusion, may play a role in transporting the low energy particles from the flank sources to midnight.