Kelvin-Helmholtz Instability and Magnetic Reconnection: Mass Transport at the LLBL

During periods of southward IMF magnetic reconnection appears to be the dominant process for the transport of magnetic flux and magnetosheath plasma into the magnetosphere. However, for northward IMF the transport of mass into the magnetosphere is not well understood. In particular for strongly parallel magnetic, fields on the two sides of the magnetopause, magnetic reconnection does not operate or is inefficient for the mass transport. For largely parallel fields the Kelvin-Helmholtz (KH) mode is unstable for k vectors largely perpendicular to the magnetic field. Although the KH mode is an ideal instability, the deformation of the boundary magnetic field through the KH can generate strong current layers and force magnetic reconnection within the KH vortex motion. We will discuss this process, onset conditions, and implications for the structure of the Low Latitude Boundary Layer (LLBL). The transport of mass appears consistent with the diffusion required at the LLBL and with the typical correlation time for the magnetospheric plasma density in response to changes in the solar wind.