In situ data for events 1 to 4 (left to right, then top to bottom). For each event, we show the mean velocity of the solar wind in km/s (top subpanel) and the radial magnetic field in nanoTesla (bottom subpanel). The ACE data, measured in situ, help us to identify the HSS corresponding to the CH event and indicate the polarity at Earth. The red and blue squares indicate the specific period of the event where a positive and negative polarity is expected, respectfully.