PROPERTIES OF INTERPLANETARY MAGNETIC-SECTOR BOUNDARIES BASED ON ELECTRON HEAT-FLUX FLOW DIRECTIONS

We have used the solar wind electron heat flux flow directions to dete rmine the interplanetary magnetic field polarities for the ISEE 3 peri od from 1978 to 1982. This technique assumes that the heat flux electr ons flow away from the Sun along magnetic field lines. It provides the field polarities independently of the field directions. The resulting distribution of sector durations and the changes in that distribution with solar activity cycle are presented for four 1-year periods. The large-scale sectors expected from extrapolation of the Stanford source surface maps are present along with a population of small-scale secto rs with a peak in the time range of 9 hour to 1 day. About half the sm all-scale sectors contain bidirectional electron (BDE) flows, suggesti ng their origins in coronal mass ejections. We also examine cases of f alse polarities, in which the directions of the fields imply polaritie s opposite to those determined from the heat-flux directions. These co nstitute only 6 to 8% of all the hourly averages of the data. The majo rity (78%) of these false polarity regions were not associated with BD Es, and 75% were of only 1 or 2 hour durations. False polarity regions tended to lie nearly orthogonal to the spiral field angles and at rel atively high latitudinal angles. While multiple (greater than or equal to 3 in 24 hours) current sheet crossings are common, we find no case s consistent with a wavy current sheet.