This list of interplanetary sector boundary crossings,
now spanning 1926-2011, has been compiled by Leif Svalgaard from ground
magnetometer data and in situ interplanetary magnetic field observations
Identification of the boundaries is discussed at the "InformationURL"
given below. For each crossing, the day of crossing, the direction of
crossing (+to- or -to+) and the durations (in whole days) of single-polarity
intervals on either side of the crossing are given. As of early 2012, the
list was being kept current.