Magnetic flux annihilation and the development of magnetic field depletions in the sectored heliosheath

The dynamics of magnetic reconnection in the sectored heliosheath isexplored with the goal of identifying signatures that can be comparedwith Voyager observations. Simulations now include much more realisticinitial conditions, including unequal magnetic fluxes in adjacentsectors and very high β. Large numbers of small magnetic islandsform early but rapidly coalesce to sector-size structures. Thelate-time magnetic structure of the sector zone differs greatly fromthat obtained in earlier simulations. Bands of unreconnected azimuthalmagnetic flux thread through the simulation domain separating regionsof depleted magnetic field strength. The depletion regions have radialscale sizes somewhat greater than the initial sector width. Theboundaries of the magnetic depletions are sharp and reveal littlechange in the direction of B. The characteristic minima of thedepletions are one third of the initial magnetic field strength. Atlate time surviving magnetic islands are widely spaced and occur inpairs. Cuts across the domain in the radial direction reveal mostlyunipolar flux except when a cut crosses one of the remnant magneticislands. This unusual late time magnetic structure is generic resultof reconnection in a high β system. The magnetic depletionsexhibit many of the properties of ``proton boundary layers'' seen inthe Voyager 1 magnetic field data. The simulations suggest that significant flux loss should take place in the heliosheath, which is consistent with Voyager measurements. The long periods of unipolar fluxseen by Voyager 1 prior to crossing the heliopause likely results fromthe annihilation of the sectors rather than an exit from the sectorzone.