Varied Types of Subauroral Polarization Streams

Subauroral polarization streams (SAPS) are narrow channels of strong westward ion flows in both the subauroral ionosphere and the conjugated inner magnetosphere in the nightside during geomagnetic storms and substorms. The SAPS exhibit different types of structures like single-peak, double-peak, multi-peak, and oscillation structures. The SAPS are closely related with ionospheric conductivity and region-2 field-aligned currents. The existence of multiple types of SAPS likely indicates precipitations from different magnetosphere-ionosphere coupling dynamics.