Large-scale properties and solar connection of the heliospheric current and plasma sheets: WIND observations

This letter presents the results of interplanetary magnetic field (IMF) analyses performed on WIND magnetometer data covering the first five months of the mission. It discusses the timing of the large scale (1-2 AU) IMF polarity changes at 1 AU and compares it to predictions that are based on a potential field solar source surface model [Hoeksema, 1989], with excellent results. General statistical properties of locally observed heliospheric current sheets, from 212 selectively chosen individual crossings, are estimated from variance analysis of their field transitions. Some of the properties discussed are: current sheet normal direction, relative B-N-component, and the rotation angle of the field in the current sheet-plane. When a related plasma sheet is present it has a complex, and difficult to characterize, magnetic field magnitude-profile. When the plasma sheet's presence is most apparent, the directional discontinuity of the field (the embedded current sheet) appears to be most abrupt, based on preliminary results from about 1/2 of the 212 cases.