Evolution of the coronal magnetic field, the areas of CHs and the SW velocity and IMF polarity during CR 2119–2124 recalculated to the source surface. Top panel for each CR: coronal magnetic field maps at the source surface from WSO (positive polarity field are light gray, negative are dark gray). Bottom panel for each CR: IMF polarity (dark gray areas represent positive polarity) as the sign of the 24 h moving average of Bx-component of IMF in the GSM coordinate system, and SW velocity (black curve). White curve is the area of the CHs calculated using the SDO/AIA data. The time axis is directed from right to left for easier comparison with the coronal field map. Black arrows show the analyzed region of the coronal magnetic field associated with the LCH (see Sect. 3).