Current sheet stress balance models of bifurcated current sheet reconnection in the solar wind

The current sheet stress balance conditions describe the equilibrium between magnetic stresses and plasma pressure across a thin current sheet. We build upon existing work developed in the context of magnetotail reconnection to derive a set of stress balance conditions for reconnection outflows in the solar wind, which are typically characterised by a bifurcated reconnection current sheet (RCS). Applying our framework to a symmetric bifurcated RCS model, we determine the outflow region opening angle and beam population properties, obtaining values consistent with observations of reconnection in the solar wind. We then validate our framework against observations of solar wind reconnection outflows from Solar Orbiter, highlighting one event with properties compatible with our simple symmetric model. For this event, we estimate an outflow region opening angle ranging from 3.4°-8.2°, in line with values reported in previous studies. We also reconstruct the outflow beam distribution functions and find that the predicted beam velocities and temperatures match observations well, although the densities are underestimated. Overall, our stress balance framework captures some of the key features of solar wind reconnection outflow, including current sheet bifurcation and counter-streaming beams. Future work will extend the framework to asymmetric reconnection geometries.