Dayside Reconnection

Dayside reconnection is exciting, unusual, and complex. To begin with, it is reconnection that occurs on the day side of the Earth (and presumably other planets with strong magnetic fields). But what is reconnection? It is the process by which magnetic fields are rearranged causing release of energy in the form of heat and kinetic energy, by accelerating local matter. Reconnection applies when magnetic fields from different sources (domains) become spliced together. This is really special because it seems to violate conservation laws in plasmas.
Its interesting to know about this from a space point of view for different reasons:

• scientifically, reconnection occurs between the interplanetary magnetic field (IMF) and the Earth's magnetic field: on the dayside energy and particles arrive at low altitudes and contribute to the aurora, on the tail side it releases energy from the tail field and can cause aurora substorms.
• technologically, devices have been made that determine the triggering of reconnection and its relationship to magnetospheric storms (NASA's THEMIS)
• and for engineers, the ESA Cluster spacecraft have been watching all this stuff happen and have demonstrated that the physics is weird, it works, and can be beautiful.

Cluster

The wikipedia reconnection page and this article about flux transfer events are good starting points for further reading.