Parametric Study of the Out-Of-Plane Tripolar Magnetic Field Component with Particle-In-Cell Simulations

Recently, it was discovered through satellite observations that magnetic reconnection can at times have a signature referred to as the out-of-the-reconnection-plane "tripolar" magnetic field. Its in situ detection both in solar wind current sheets and at Earth's dayside magnetopause, and subsequent identification in particle-in-cell (PIC) simulations, has been interpreted as supporting evidence for the presence of multiple X-lines (the loci along the current sheet where the change in magnetic topology takes place). Since the tripolar field signature's discovery, there has not been a comprehensive study to understand which external (boundary) magnetic field and plasma conditions give rise to it. Here, we use a 2.5-D PIC code to address this problem. We perform a number of idealized PIC simulations of magnetic reconnection exploring both symmetric and asymmetric magnetic field and plasma configurations across the reconnecting current sheet. For each set of initial boundary conditions, we investigate the tripolar signature's appearance for both component and anti-parallel reconnection scenarios with varying density, temperature, and magnetic field profiles. For the component reconnection cases, the role of the guide- field component strength on the tripolar signature's occurrence is also analyzed.