Interplanetary disturbances around the solar minimum of cycle 22

In situ solar wind observations and solar observations from space enable us to investigate interplanetary disturbances and their solar sources. Recurrent high-speed streams from coronal holes around the solar minimum of cycle 22 have been observed. However, many geomagnetic storms are associated with CMEs even at the solar minimum. Coronal mass ejections (CMEs) have sometimes been observed in these high-speed streams. Geomagnetic storms associated with CMEs tend to be strong disturbances with short duration. Those associated with high-speed streams tend to be moderate disturbances with long duration. Both characteristics are seen in geomagnetic disturbances associated with both high-speed streams and CMEs.