@article{oai:nagoya.repo.nii.ac.jp:00018490, author = {Saito, Takao and Oki, Tosio}, issue = {2}, journal = {Proceedings of the Research Institute of Atmospherics, Nagoya University}, month = {Nov}, note = {Conditions of the sun and the heliosphere are studied in relation to the intense disturbances of the earth's and cometary magnetospheres in February and March, 1986. In this sunspot minimum phase, the sun had essentially the southward axial dipole which was to produce a weak northward IMF. However, one bipolar magnetic region in the northern hemisphere of the sun was connected by "southward" magnetic loops to another bipolar magnetic region in the southern hemisphere, because the two regions were near the equator by the Maunder's butterfly law. The meridional connection on 60° heliolongitude formed an abnormal giant bipolar magnetic region (GBMR), which made a local and strong warp of the general equatorial neutral line on the solar source surface. Magnetic energy was deposited and confined by the southward magnetic loops from the meridional GBMR, from which a slow-speed solar wind blew for a few months. Then, an abnormally active :flare cluster started suddenly at the center of the meridional GBMR and the high-speed flare plasma broke the meridional magnetic loops, conveying the southward magnetic field towards the earth. After the flares, the GBMR decayed and the local warp of the neutral sheet was dissolved. Abnormally large-amplitude diurnal anisotropy of cosmic ray neutron intensity during the earth storm is explained by a combination of the minimum-phase effect and the storm effect. On the other hand, abnormally intense magnetic storm is explained by the high-speed flare plasma with southward IMF. The flattened interplanetary neutral sheet is discussed to explain the reported disconnection events of the plasma tail of comet Halley., This special issue contains contributed papers presented at the symposium "Solar Terrestrial Events in February-March 1986" (January 19, 1989, Nagoya)}, pages = {27--39}, title = {THE SUN AND THE HELIOSPHERE IN FEBRUARY-MARCH, 1986}, volume = {36}, year = {1989} }