Sectors in the distant heliosphere: Voyager 1 and 2 observations from 1999 through 2002 between 57 and 83 AU

Sectors and sector boundaries were observed by Voyager 1 (V1) and Voyager 2 (V2) from 1999 through 2002 in the distant heliosphere. V1 moved from a heliocentric distance R = 72.5 to 83.4 AU and from a latitude of delta = 33.4degrees to 33.8degrees from 1999.0 to 2002.0, and V2 moved from R = 56.7 to 69.0 AU and from delta = -20.2degrees to -24.1degrees from 1999.0 to 2003.0. During some time intervals, sectors were not present, and during much of the time the data were not sufficiently accurate to determine whether or not sectors were present. Nevertheless, some sectors do persist out to 83 AU, even in the interval surrounding the solar maximum. A regular sector pattern was not observed by either V1 or V2 in any of the years from 1999 through 2002. The sector sizes are highly variable, and they are not consistent with either a two-sector pattern or a four-sector pattern. The sector pattern observed at 1 AU by ACE was presumably destroyed by stream interactions and by transient ejecta that moved through the heliosphere. Observations of the solar wind speed made by V2 from 1999 to 2002 show a jump-ramp structure, as expected from previous observational and theoretical studies. The jump-ramp structures are much larger than the sectors. The speed jumps occur within some of the sectors, not at the sector boundaries.