Evolution of recurrent solar wind structures between 14 AU and the termination shock

An MHD simulation model is used to extrapolate the solar wind conditions observed from Voyager 2 at approximately 14 AU to the region of the outer heliosphere bounded by the termination shock. The paper presents two simulation results. In 1984, Voyager 2 observed two sets of nearly recurrent solar wind interaction regions, each with a period of approximately 26 days. The first set was observed between days 45 and 120 and the second set between days 290 and 365. Initial conditions for the two simulation studies representing recurrent solar wind structures were generated by repeating the pattern of plasma and magnetic field variations respectively observed during one solar rotation in March 1984 at 13.8 AU and a similar pattern observed in November 1984 at 15.4 AU. Each simulation result describes an idealized recurrent solar wind structure in the supersonic region of the outer heliosphere out to the termination shock far beyond the present reaches of the Pioneer and Voyager spacecraft. The solar wind plasma is heated and compressed by a pair of forward‐reverse interplanetary shocks. The shocks may accelerate or decelerate as they move through the nonuniform medium. A collision between the forward shock and the reverse shock occurs approximately every 40 AU. The shocks are weakened after each collision. The termination shock is weakened and moves outward when a forward shock interacts with it, and the termination shock is strengthened and moves inward when a reverse shock interacts with it.