Interaction of CME/ICME with HSS solar wind from coronal holes: case study

In this paper we look for traces of interaction of CME/ICME with high-speed stream (HSS) of solar wind from coronal hole (CH) for two serial Carrington rotations (CRs) during December 2011 - January 2012. We analyze two cases. (1) In CR 2118 instead of predicted arrival of HSS the signatures of ICME with modified back side and compressed slow stream were observed. (2) In CR 2119 the predicted HSS was observed in time, and after arrival of preceding ICME. Our analysis shows that difference of these cases can be explained by different interactions between HSS and CME, which in the first case result in significant deflection of HSS of solar wind from the Sun-Earth line. Thus, the CH passage through the central meridian with simultaneous occurrence of CMEs in the nearby located sources can result in interaction between HSS and CME streams, deflection of the HSS stream aside of the ecliptic and changes in parameters of the solar wind.