The Impact of Plasmapheric Mass Loading on Dayside Reconnection

Thursday, 18 December 2014: 5:15 PM
Jeremy Ouellette1,2, John Lyon2, Oliver Brambles3, Binzheng Zhang3, William Lotko3,4 and Michael James Wiltberger4, (1)Vermont Technical College, Department of Computer & Information Systems, Randolph Center, VT, United States, (2)Dartmouth College, Department of Physics & Astronomy, Hanover, NH, United States, (3)Dartmouth College, Thayer School of Engineering, Hanover, NH, United States, (4)National Center for Atmospheric Research, High Altitude Observatory, Boulder, CO, United States
We present results of a global-scale MHD study of the effect of plasmapheric mass on dayside reconnection during the plasmaphere's sunward surge after the onset of southward IMF conditions. We find that the local reconnection rate is reduced in regions where the plume impinges on the dayside magnetopause, though less than predicted by the Cassak-Shay theory. In simulations without a plasmasphere, the theory tends to overestimate the reconnection rate, thereby predicting a stronger reduction in the rate of merging when plasmapheric mass is introduced. We also find that the dayside reconnection potential is reduced, though the effect is less than would be predicted with more uniform loading of mass inside the magnetosphere. This suggests that both the location and spatial extent of plasmapheric plumes play important roles in determining the degree to which dayside reconnection activity is reduced by magnetospheric mass loading.