Origin, geometry and efficiency of the interaction regions

The stream interaction regions (SIRs) are large-scale structures of the solar wind and are formed due to the interaction between fast and slow streams. It is necessary to understand the evolution, geometry, and efficiency of the SIRs due to the important role they play in space weather prediction. Based on WIND spacecraft in-situ observations, we analyzed a set of SIRs that were registered during the period 2018-2019. We studied some characteristics of the SIRs such as their radial width, momentum transfer between the fast and the slow streams, the relative position of the stream interfase (SI), and the orientation of the SI. In addition, we measured the efficiency of each SIR using global (Kp (estimated global index), and Dst (Disturbance storm time)) and local (Kmex, and Dst-mex) geomagnetic indices. The properties of the source regions of high-speed solar wind streams are also discussed. Finally, we examined the position of the heliospheric current sheet which would be related to the efficiency of a SIR.