Particle precipitation patterns in the dayside polar region for strongly northward IMF Original Research Article

A detailed analysis of precipitation particle and electric field data from two DE 2 (northern and southern) polar passes during strongly northward interplanetary magnetic field has been made. The satellite tracks of these two passes are very similar in INVMLT-INVLAT coordinates, and we identified interhemispherical difference in the relation of various plasma regimes with the convection flow. One of the prominent differences is that the cusp/mantle precipitation can be seen at 85° INVLAT in the sunward flow region of the reverse convection pattern in the summer ionosphere, and that at similar latitudes of the winter ionosphere a different type of the ion precipitation, which is referred to as the very high-latitude ion precipitation (VHI), occurs instead of the cusp although a sunward (weaker) flow region can be seen. It is also found that the region that includes the cusp/mantle, VHI, the polar cap, and its boundary-like region shifts toward the dawn (dusk) in the northern (southern) hemisphere with almost the same transpolar distance between in both hemispheres.