Magnetic reconnection between the interplanetary magnetic field (IMF)
and the geomagnetic field is the important if not dominant process for mass, energy and momentum transfer from the Earth's magnetosheath to the magnetosphere. While reconnection is generally recognized as important, the details of the process are still under investigation and remain poorly understood.
The anti-parallel reconnection hypothesis states that reconnection
occurs at or near the region of magnetic field lines of exactly opposite polarity. However, recent observations have pointed to significant reconnection rates in regions with less than anti-parallel field share. For this component reconnection hypothesis, share angle as small as 50 degree between the magnetosheath and magnetospheric magnetic fields participating in reconnection have been observed. This presentation will review the current evidence for anti-parallel and component reconnection and how to remotely track the reconnection site.