Structure of exhaust jets produced by magnetic reconnection localized in the out‐of‐plane direction

Abstract

AbstractThree‐dimensional electromagnetic particle‐in‐cell simulations are used to investigate the structure of exhaust jets produced by magnetic reconnection localized in the out‐of‐plane direction. The localized reconnection is produced by periodically blocking the cross‐tail current density, a procedure that has effects analogous to those produced by the assumption of a region of anomalous resistivity in fluid treatments of reconnection. The width of the blocking region is varied between 4 and 24di, where di is the ion inertial length. After an initial displacement in the electron‐drift direction, the jet front undergoes a marked expansion in the ion‐drift direction, reaching a total cross‐tail width of 15–20di regardless of the initial width. The jet front breaks up into small‐scale finger structures of the order of 1–2di in width, which appears to be due to the action of the ballooning/interchange instability. Ahead of the front, the ion pressure Pixx is increased due to reflection of ions from the moving front and the penetration of high‐speed ions in the jet through the front. The ion temperature Tixx exhibits a minimum within the front, while the electron temperature is enhanced in the front. The properties of the reconnection‐generated fronts are compared and contrasted with those of interchange heads produced by a decreasing entropy profile.