TY - JOUR AB - We report new multi-spacecraft Cluster observations of tripolar guide magnetic field perturbations at a solar windreconnection exhaust in the presence of a guide field BM which is almost four times as strong as the reversing fieldBL. The novel tripolar field consists of two narrow regions of depressed BM, with an observed 7%–14% ΔBMmagnitude relative to the external field, which are found adjacent to a wide region of enhanced BM within theexhaust. A stronger reversing field is associated with each BM depression. A kinetic reconnection simulation forrealistic solar wind conditions and the observed strong guide field reveals that tripolar magnetic fields preferentiallyform across current sheets in the presence of multiple X-lines as magnetic islands approach one another and mergeinto fewer and larger islands. The simulated ΔBM/ΔXN over the normal width ΔXN between a BM minimum andthe edge of the external region agree with the normalized values observed by Cluster. We propose that a tripolarguide field perturbation may be used to identify candidate regions containing multiple X-lines and interactingmagnetic islands at individual solar wind current sheets with a strong guide field. AU - Carr,CM AU - Erikksson,S AU - Lapenta,G AU - Newman,DL AU - Phan,TD AU - Gosling,JT AU - Lavraud,B AU - Khotyaintsev,YV AU - Markidis,S AU - Goldman,MV DO - 1/43 PY - 2015/// SN - 0004-637X TI - On Multiple Reconnection X-lines and Tripolar Perturbations of Strong Guide Magnetic Fields T2 - The Astrophysical Journal UR - http://dx.doi.org/10.1088/0004-637X/805/1/43 UR - http://hdl.handle.net/10044/1/23240 VL - 805 ER -