Scaling of reconnection at the dayside magnetopause [presentation]
Ouellette, J., Rogers, B., Lyon, J., & Wiltberger, M. (2009). Scaling of reconnection at the dayside magnetopause [presentation]. In AGU Fall Meeting 2009. American Geophysical Union: San Francisco, CA, US.
Using the Lyon-Fedder-Mobarry (LFM) magnetospheric simulation code we have studied the dependence of the reconnection rate at the subsolar point on solar wind parameters for southward IMF conditions. We find that this rate scales with the solar wind electric field as approximately Erx ≈ 0.46 Esw ... Show moreUsing the Lyon-Fedder-Mobarry (LFM) magnetospheric simulation code we have studied the dependence of the reconnection rate at the subsolar point on solar wind parameters for southward IMF conditions. We find that this rate scales with the solar wind electric field as approximately Erx ≈ 0.46 Esw = 0.46 vsw BIMF. By the Rankine-Hugoniot conditions, this also implies the reconnection field scales the same with the magneotsheath electric field just inside the bow shock. Therefore, approximately half the flux convected towards the magnetopause in the noon-midnight plane is reconnected there, with most of the field lines deflecting out of plane as they journey through the magnetosheath. This scaling law is robust and holds for a variety of solar wind velocities and magnetic field strengths. We have also uncovered two aspects of magnetopause reconnection that are not present in two-dimensional theories, such as the Petschek and Sweet-Parker models. First, the current layer varies with the magnetopause curvature, and is set by the solar wind conditions. Second, small bow shock standoff distance caused by strongly super-Alfvenic solar wind speeds cause the plasma to flow parallel to the dissipation region at its ends. Finally, we have found that the Cassak-Shay theory overestimates the reconnection rate at the magnetopause by a factor of five due to its prediction of the speed plasma flows out of the diffusion region. Show less